GAtherton, Author at Aspergillosis Patients & Carers Support

Scientific illustration showing amphotericin B disrupting an Aspergillus fungal cell membrane during research into antifungal resistance.

Amphotericin B resistance in Aspergillus: protecting an important treatment for the future

Amphotericin B is one of the oldest antifungal medicines still used in specialist care. It remains important because it works differently from azole antifungals such as itraconazole, voriconazole, posaconazole and isavuconazole.

Resistance to azole antifungals is an increasing clinical concern in aspergillosis. Amphotericin B resistance can occur, but it is much less commonly encountered in routine patient care.

For most people with aspergillosis, this research is not a reason to worry that amphotericin B will fail if it is needed. Instead, recent research is helping scientists understand how amphotericin B resistance develops and how this valuable treatment might be protected or improved for the future.

What is amphotericin B?

Amphotericin B is an antifungal medicine that damages the fungal cell membrane. It binds to ergosterol, an important component of that membrane, causing damage that can lead to fungal cell death.

It is available in different formulations, including liposomal amphotericin B. It may be used for serious or invasive fungal infections, particularly when azole treatment is unsuitable, ineffective or affected by resistance.

Amphotericin B is valuable partly because it attacks fungi in a different way from the azoles. More information about antifungal treatment is available in our guide to the management of aspergillosis.

What did the original study find?

The original article on this website described a 2019 study from Brazil. Researchers tested 228 Aspergillus isolates and found that 27% of the Aspergillus fumigatus isolates tested showed reduced susceptibility or resistance to amphotericin B.

This was an important warning, but the figure needs careful interpretation. It did not mean that 27% of patients with aspergillosis had amphotericin B-resistant infections. The isolates came from a particular study population and cannot be used to estimate the risk for all patients.

Laboratory resistance results also do not always translate directly into treatment failure. The species of Aspergillus, the type of infection, the patient’s immune system, the drug formulation and the laboratory method used for susceptibility testing all matter.

How is this different from azole resistance?

Azole resistance is currently the more important resistance problem in clinical aspergillosis.

Azole resistance may develop during long-term treatment, but resistant Aspergillus strains can also be acquired from the environment. When resistance is suspected, it can make treatment more difficult because azoles are commonly used for several forms of aspergillosis.

Amphotericin B resistance is less commonly encountered in clinical practice. It remains an important alternative in some situations because it has a different mechanism of action.

That difference is valuable. If resistance to one antifungal class develops, another class may still be effective. Treatment decisions are made by specialist teams using the patient’s clinical condition, laboratory results and response to treatment.

New research is explaining how resistance works

Recent laboratory research is beginning to identify possible mechanisms behind amphotericin B resistance.

A 2024 study of A. fumigatus found that exposure to amphotericin B affected proteins involved in membrane transport, lipid handling and fungal metabolism. One protein, called RtaA, appeared to influence the movement or organisation of sterols within the fungal cell. Changes involving RtaA altered the fungus’s sensitivity to amphotericin B.

This does not mean that RtaA testing is currently available for patients. The finding is experimental. Its importance is that it gives researchers a possible biological pathway to investigate when developing new treatments or resistance tests.

Read the study on RtaA and amphotericin B resistance.

A separate 2025 study examined Aspergillus terreus. This species is already known to have naturally reduced susceptibility to amphotericin B. The researchers found that changes in fungal growth and genetic activity could alter amphotericin B susceptibility, highlighting how complicated resistance can be within a single species.

Read the study of Aspergillus terreus and amphotericin B susceptibility.

Why does species identification matter?

Not all Aspergillus species respond to antifungal medicines in the same way.

Some non-fumigatus Aspergillus species may have higher amphotericin B minimum inhibitory concentrations in laboratory testing. However, interpreting these results is difficult because clinical breakpoints are not available for every species, and studies may use different laboratory methods.

This is one reason specialist laboratories and clinical teams need to interpret susceptibility results in context. A laboratory result is not, by itself, a prediction of what will happen to an individual patient.

Could newer medicines preserve the benefits of amphotericin B?

Researchers are also developing newer polyene antifungals. Polyenes are the drug family that includes amphotericin B.

One example is SF001, an experimental next-generation polyene. Laboratory studies suggest that it may retain broad antifungal activity, including activity against some amphotericin B-resistant isolates, while potentially causing less toxicity.

SF001 is not yet a routine treatment and requires further development and clinical testing. However, this research illustrates how understanding resistance mechanisms may help scientists develop safer and more effective medicines for the future.

Read the study of SF001 and amphotericin B.

What does this mean for patients?

For most people living with aspergillosis:

amphotericin B resistance is not a common everyday concern;
azole resistance is currently the more important clinical resistance problem;
a laboratory finding of reduced susceptibility does not automatically mean treatment will fail;
species identification and specialist interpretation are important;
treatment decisions depend on the type of aspergillosis, the patient’s health, drug levels, side effects and laboratory results.

Patients receiving long-term azole treatment may need regular monitoring of symptoms, blood tests, liver function and antifungal drug levels. This is known as therapeutic drug monitoring and can help clinicians judge whether treatment exposure is adequate and whether side effects are developing. See our information about antifungal monitoring and therapeutic drug monitoring.

Protecting an important treatment for the future

Recent research is moving beyond simply detecting resistance. Scientists are beginning to understand the biology behind amphotericin B resistance and are using that knowledge to explore new and potentially safer antifungal medicines.

Amphotericin B resistance is not currently the same kind of widespread clinical problem as azole resistance. For most patients, this research is not a reason to expect treatment failure.

Its importance is that amphotericin B remains a valuable antifungal option, and research into resistance may help preserve or improve the polyene medicines available to patients with serious fungal infections in the future.

References

Abou-Kandil et al. The proteomic response of Aspergillus fumigatus to amphotericin B reveals the involvement of the RTA-like protein RtaA in AmB resistance. MicroLife.
Eisele et al. Aspergillus terreus sectorization: a morphological phenomenon shedding light on amphotericin B resistance mechanism. mBio. 2025.
Vahedi-Shahandashti and Lass-Flörl. In vitro activity of SF001: a next-generation polyene versus amphotericin B. Antimicrobial Agents and Chemotherapy. 2025.

by GAtherton

Patient discussing NTM lung disease and aspergillosis with a respiratory clinician while reviewing CT scans

NTM Lung Disease and Aspergillosis: Why They Can Overlap

Nontuberculous mycobacteria (NTM) and aspergillosis are different types of lung disease, but they can sometimes occur together. Both may develop in lungs that have already been damaged by bronchiectasis, COPD, previous tuberculosis or other chronic conditions.

When NTM and aspergillosis overlap, symptoms and CT scan changes can be difficult to interpret. It may not be immediately clear whether deterioration is caused by NTM, chronic pulmonary aspergillosis (CPA), another infection, or more than one condition at the same time.

What is NTM lung disease?

Nontuberculous mycobacteria are environmental bacteria related to the organism that causes tuberculosis. They are found naturally in soil, water, dust and plumbing systems.

There are many species of NTM. Those most commonly associated with lung disease include:

Mycobacterium avium complex (MAC)
Mycobacterium abscessus complex
Mycobacterium kansasii

NTM are not the same as tuberculosis and, in general, NTM lung disease is not spread from person to person.

Many people encounter NTM without becoming ill. Infection is more likely when the lungs are already damaged or when the immune system cannot clear the bacteria effectively.

How does NTM affect the lungs?

NTM can cause a long-term inflammatory infection in the lungs. It may produce nodules, bronchiectasis, cavities or areas of lung inflammation.

Symptoms may include:

persistent cough
increasing sputum
breathlessness
fatigue
weight loss
low-grade fever or night sweats
recurrent chest infections
coughing up blood

Some people have NTM detected in a respiratory sample without clear evidence of active lung disease. This may be described as NTM isolation or colonisation. Active NTM pulmonary disease requires the clinical, radiological and microbiological findings to fit together.

Why can NTM and aspergillosis occur together?

Both conditions are more likely when the lungs have structural damage. Bronchiectasis and cavities can make it easier for NTM and Aspergillus to remain in the lungs.

Several factors may contribute:

damaged or widened airways
cavities within the lungs
impaired mucus clearance
persistent inflammation
repeated antibiotic or steroid treatment
low body weight or poor nutritional status
reduced immune protection

NTM infection may further damage lung tissue, creating conditions in which Aspergillus can grow. Conversely, existing Aspergillus-related disease may make the lungs more vulnerable to NTM.

What forms of aspergillosis may occur?

Several different Aspergillus-related conditions can occur in people with NTM lung disease.

Chronic pulmonary aspergillosis (CPA), a long-term fungal infection
chronic cavitary pulmonary aspergillosis
chronic fibrosing pulmonary aspergillosis
Aspergillus nodules
an aspergilloma or fungal ball within a cavity
less commonly, subacute invasive pulmonary aspergillosis

A positive Aspergillus culture or blood test does not automatically mean that active CPA is present. Aspergillus may sometimes be detected in damaged airways without causing progressive disease.

Why can the diagnosis be difficult?

NTM and CPA can cause similar symptoms and similar changes on CT scans. Both may produce:

cavities
nodules
bronchiectasis
lung inflammation
progressive scarring
persistent cough and sputum
weight loss and fatigue

This means that a new cavity or worsening scan does not always identify which infection is responsible.

Doctors may need to compare scans over time and look for clues such as:

a new or enlarging cavity
a fungal ball within a cavity
progressive fibrosis around a cavity
increasing pleural thickening
new nodules or areas of consolidation
symptoms that continue despite treatment for NTM

CT findings can suggest CPA, but they need to be interpreted alongside blood tests, sputum results and the clinical course.

What does recent research show?

A 2026 multicentre prospective study followed 365 people with respiratory samples positive for NTM, including MAC, M. kansasii and M. abscessus complex.

Approximately one-third had raised Aspergillus-specific IgG, while 9% developed CPA during the study period. CPA was more common in people with active NTM pulmonary disease than in those with NTM detected without clear evidence of active disease.

The risk of CPA increased over time. Among people with active NTM pulmonary disease, the cumulative incidence of CPA was approximately 2.7% at one year, 8.3% at two years and 14.7% at three years.

People who developed CPA had a higher risk of radiological progression and poorer overall survival. The study also found that some people who initially had a negative Aspergillus IgG test later became positive, suggesting that the result can change during follow-up.

These findings do not mean that everyone with NTM needs antifungal treatment. They do suggest that new or worsening symptoms and CT changes should prompt consideration of CPA, particularly in people with cavities, active NTM disease or repeated steroid treatment.

How is NTM lung disease diagnosed?

Diagnosis usually requires three types of evidence:

symptoms or other clinical evidence of lung disease
compatible changes on chest imaging
repeated or otherwise convincing microbiological evidence of NTM

A single positive sputum sample does not always prove active NTM lung disease. NTM can sometimes be present in the airways without causing progressive infection.

Testing may include:

sputum cultures for mycobacteria
chest X-rays and CT scans
bronchoscopy and bronchoalveolar lavage
lung-function tests
blood tests and inflammatory markers

How is CPA investigated?

Assessment for CPA may include:

symptoms and how they have changed
comparison of serial CT scans
Aspergillus-specific IgG
sputum culture or PCR for Aspergillus
galactomannan testing in selected circumstances
bronchoscopy or tissue sampling when necessary

A raised Aspergillus IgG supports the possibility of CPA but does not prove it on its own. People with structural lung disease may have raised antibody levels without active CPA, so the result must be interpreted with the CT findings and clinical progression.

Can treatment for one condition affect the other?

Yes. Treatment can be complicated when NTM and CPA occur together.

NTM treatment often involves several antibiotics over many months. CPA may require a prolonged course of an oral azole antifungal. These medicines can interact with one another and may affect liver function, heart rhythm or the blood levels of other medicines.

It is therefore important that treatment is coordinated between respiratory, infectious-disease and fungal-disease specialists where appropriate.

Corticosteroids may also require careful consideration. They can be essential for some people with asthma, ABPA or other inflammatory conditions, but they may reduce the immune response that helps control NTM and Aspergillus.

Medicines should never be stopped or changed without advice from the treating team.

What does this mean for someone with NTM?

Having NTM detected in a respiratory sample does not mean that you will develop aspergillosis. Many people with NTM do not develop CPA.

Further assessment may be particularly important if you develop:

new or worsening breathlessness
persistent cough or sputum despite NTM treatment
unexplained weight loss or fatigue
new or enlarging cavities on CT
new haemoptysis
progressive changes despite apparently successful treatment
repeated courses of steroids

These symptoms can have many causes. They do not automatically mean that CPA is present, but they deserve review rather than being attributed to NTM alone.

Key message: NTM and aspergillosis are different diseases, but they can coexist in structurally damaged lungs. Because symptoms and CT findings overlap, diagnosis may require repeated assessment, Aspergillus IgG testing, sputum microbiology and comparison of scans over time.

Reducing exposure to NTM

NTM are environmental organisms and cannot be avoided completely. They are commonly found in soil, dust, natural water and household plumbing.

People with chronic lung disease may choose to reduce exposure to heavily aerosolised water or soil by:

avoiding breathing in steam from hot tubs or spa pools
using care around dusty soil, compost and potting mix
wearing a well-fitting mask when gardening or working with dusty materials
maintaining nebulisers and humidifiers carefully
following local advice about water and plumbing hygiene

These measures cannot guarantee prevention and should not become a source of anxiety. Discuss personal precautions with your healthcare team.

Related information

Paper of the week: treating an abscess inside a CPA cavity

A case report describes a person with chronic pulmonary aspergillosis who developed a lung abscess inside an existing pulmonary cavity.

The abscess was successfully treated using percutaneous drainage, a procedure in which a catheter is passed through the chest wall into the infected area to allow the contents to drain. This was used alongside antifungal treatment.

Most people with CPA do not develop this complication. However, the report illustrates how the appearance of a cavity can change over time and why new symptoms or changes on scans may require further investigation.

A worsening cavity does not always mean that antifungal treatment has simply failed. There may be an additional problem, such as an abscess, bacterial infection or obstruction, requiring a different treatment approach.

This was a single case report, so it cannot tell us how often this approach will be useful. It does, however, show that drainage may occasionally provide an additional treatment option when infection becomes trapped within a cavity.

Read the case report on PubMed

Dense mucus on CT may help identify ABPA

A radiology report has highlighted the importance of high-attenuation mucus in allergic bronchopulmonary aspergillosis.

In ABPA, thick mucus can collect inside widened airways. On a CT scan, some mucus appears unusually dense or bright. This is called high-attenuation mucus.

Although it is not present in every person with ABPA, this finding can be a useful clue, particularly when someone has difficult-to-control asthma, bronchiectasis, eosinophilia or evidence of sensitisation to Aspergillus.

The finding is important because mucus plugging can contribute to:

worsening cough and wheeze;
repeated chest infections;
blocked airways;
temporary or permanent changes in lung function; and
the development or progression of bronchiectasis.

A CT scan is only one part of the diagnostic process. High-attenuation mucus does not diagnose ABPA on its own, and its absence does not exclude ABPA. Doctors also consider symptoms, asthma or bronchiectasis, blood tests and the overall pattern on imaging.

Read the radiology report on PubMed

Genetic variants did not predict viral-associated aspergillosis

A multicentre study investigated whether common genetic variants in two immune-related genes—PTX3 and CLEC7A, also known as Dectin-1—were associated with invasive pulmonary aspergillosis following severe influenza or COVID-19.

The study did not find an association between these genetic variants and either the occurrence or outcome of invasive pulmonary aspergillosis.

This is useful information, but it does not mean that genetics are irrelevant to aspergillosis. The immune system involves many genes, and susceptibility may depend on combinations of genetic variants, the type of underlying illness, immune treatments and the particular form of aspergillosis.

It does show that testing one or two common genetic variants is unlikely to provide a simple way of predicting who will develop viral-associated aspergillosis.

Read the study on PubMed

Early signs of resistance to olorofim

Olorofim is a newer antifungal drug being developed for difficult-to-treat fungal infections. Laboratory researchers have identified amino-acid changes in Aspergillus flavus that can reduce susceptibility to olorofim.

This is laboratory research rather than evidence that olorofim resistance is already widespread in patients. Nevertheless, it is important because antifungal resistance can reduce the effectiveness of treatment.

Whenever a new antifungal becomes available, doctors and laboratories need to monitor:

whether resistant strains are already present;
whether resistance develops during treatment;
how resistance is detected; and
whether a different antifungal is needed.

The study involved Aspergillus flavus, whereas many chronic lung infections are caused by Aspergillus fumigatus. The findings therefore cannot be applied directly to every person with aspergillosis. They are an early warning that resistance testing will remain important as new treatments are introduced.

Read the study on PubMed

Why voriconazole blood tests remain important

Voriconazole is affected by genetic differences in an enzyme called CYP2C19. Some people process the drug quickly, while others process it more slowly.

A case report describes a patient with a CYP2C19 result expected to indicate normal metabolism. Despite this, she required a much higher-than-usual dose of voriconazole to achieve therapeutic blood concentrations.

The authors also noted that increased C-reactive protein, or CRP, appeared to be associated with reduced CYP2C19 activity. Inflammation may therefore alter how the body processes voriconazole, even when genetic testing suggests that metabolism should be normal.

This is one reason why a genetic result cannot replace therapeutic drug monitoring. Blood tests can show whether enough voriconazole is present to be effective without reaching unnecessarily high concentrations.

The report does not mean that people with inflammation should automatically receive higher doses. It describes one patient, and dose changes must be guided by clinical review and blood-level monitoring.

Read the case report on PubMed

What does this mean for patients?

The papers published this week reinforce several practical points:

New or worsening symptoms during CPA may need investigation for complications rather than being assumed to represent simple treatment failure.
CT findings can provide important clues in ABPA, especially when thick mucus blocks widened airways.
Genetic testing is unlikely to give a complete answer about susceptibility to aspergillosis.
Resistance to new antifungals must be monitored as these drugs enter clinical use.
Voriconazole doses cannot always be predicted accurately from genetics alone, which is why therapeutic drug monitoring is so valuable.

As usual, these studies add to our understanding but do not replace individual medical assessment. Decisions about antifungal treatment, drainage procedures or drug doses should be made by the clinical team caring for the patient.

by GAtherton

Doctor reviewing spirometry, CT imaging and lung diagrams to assess COPD, bronchiectasis and overlapping lung disease

COPD, Bronchiectasis and Aspergillosis: Understanding Overlapping Lung Conditions

Doctor reviewing spirometry, CT imaging and lung diagrams to assess COPD, bronchiectasis, aspergillosis and overlapping lung disease — Diagnosing overlapping lung conditions may involve combining symptoms, lung-function tests, CT scans and Aspergillus testing.

Bronchiectasis and chronic obstructive pulmonary disease (COPD) are different lung conditions, but they can cause many of the same symptoms. Some people also have both conditions at the same time.

This overlap can make diagnosis difficult. It is one reason why doctors may review or refine a diagnosis when symptoms persist, test results change or treatment does not have the expected effect.

Aspergillosis can add another layer of complexity. COPD and bronchiectasis may create the damaged-lung environment in which chronic pulmonary aspergillosis develops, while Aspergillus can also cause allergic or airway disease such as ABPA and Aspergillus bronchitis.

These conditions may share symptoms such as cough, sputum, breathlessness, fatigue, recurrent infections and changes on CT scans. A person may have one condition, two overlapping conditions or several contributing problems at the same time.

The key difference

The simplest distinction is:

COPD mainly causes persistent airflow obstruction, while bronchiectasis is permanent structural damage and widening of the airways.

However, this is an oversimplification. Both conditions can involve airway inflammation, mucus, infection, reduced lung function and progressive lung damage.

What is COPD?

Chronic obstructive pulmonary disease (COPD) is a long-term condition in which airflow through the lungs becomes restricted.

COPD mainly includes two overlapping types of lung damage:

Chronic bronchitis: long-term inflammation of the airways, often with increased mucus production and a persistent cough.
Emphysema: damage to the small air sacs in the lungs, reducing the area available for oxygen to pass into the blood.

COPD can also cause narrowing of the smaller airways, trapping of air and difficulty breathing out fully.

Symptoms may include:

breathlessness, especially during activity
a persistent cough
regular production of sputum
wheezing or chest tightness
repeated chest infections
reduced exercise tolerance
fatigue

COPD is often associated with smoking, but it can also result from long-term exposure to air pollution, occupational dusts and fumes, previous infections, childhood lung problems or genetic conditions such as alpha-1 antitrypsin deficiency.

What is bronchiectasis?

Bronchiectasis is a long-term condition in which one or more airways become permanently widened, thickened or scarred.

Healthy airways use mucus and tiny hair-like structures called cilia to remove dust, microbes and other particles. In bronchiectasis, damaged airways often clear mucus less effectively. Mucus can collect in widened parts of the airway, allowing bacteria and fungi to remain in the lungs for longer.

Bronchiectasis may develop after:

severe or repeated chest infections
tuberculosis or other lung infections
immune-system problems
asthma or allergic bronchopulmonary aspergillosis
cystic fibrosis or primary ciliary dyskinesia
autoimmune or inflammatory conditions
airway blockage or inhaled foreign material

Sometimes no clear cause is found.

Common symptoms include:

a long-term cough
regular production of sputum
repeated chest infections
breathlessness
wheezing
fatigue
coughing up blood

Find out more about mucus clearance and airway-clearance techniques.

Why are widened airways a problem?

It may seem that wider airways should make breathing easier. In bronchiectasis, however, widening is a sign that the airway walls have been damaged and weakened.

The widened airways may become floppy and lose their normal ability to move mucus upwards. Mucus can pool in the enlarged sections, where bacteria and fungi may remain and multiply.

This creates a self-reinforcing cycle:

airway damage → widening → mucus retention → infection and inflammation → further airway damage

So, although COPD is often associated with airways that are too narrow, bronchiectasis involves airways that are too damaged and inefficient to clear mucus properly.

How are the conditions diagnosed?

Respiratory diagnoses are not usually based on symptoms or lung function alone. Doctors combine:

symptoms and medical history
spirometry and other lung-function tests
CT imaging
sputum and blood tests
examination findings
response to treatment

A useful way to think about this is:

Lung function measures what the lungs can do; imaging shows what has happened to their structure.

Diagnosing COPD

COPD is mainly identified by persistent airflow obstruction. Spirometry measures how much air a person can breathe out and how quickly they can do so.

Current COPD guidance uses post-bronchodilator spirometry to confirm persistent airflow obstruction. Other information, including symptoms, smoking history, CT scans and exacerbations, helps assess the wider disease.

Diagnosing bronchiectasis

Bronchiectasis is fundamentally an anatomical diagnosis. A thin-section or high-resolution CT scan is usually needed to show that the airways are permanently widened or distorted.

Lung function in bronchiectasis may be:

normal
obstructive
restrictive
mixed

A normal spirometry result therefore does not exclude bronchiectasis.

Can someone have both COPD and bronchiectasis?

Yes. COPD and bronchiectasis can coexist, particularly in people with more advanced lung disease, frequent exacerbations or persistent sputum production.

When both conditions are present, a person may have:

greater breathlessness
more frequent exacerbations
greater sputum production
more persistent airway infection
more complex treatment needs

The correct conclusion may not be that someone has COPD instead of bronchiectasis. They may have COPD and bronchiectasis, with each condition contributing to their symptoms.

Where does aspergillosis fit?

People with COPD or bronchiectasis may be more vulnerable to Aspergillus-related disease because their lungs or airways are already damaged.

Possible conditions include:

chronic pulmonary aspergillosis
Aspergillus bronchitis
allergic bronchopulmonary aspergillosis
Aspergillus sensitisation
Aspergillus colonisation without active disease

These conditions are different. A positive sputum culture or blood test does not automatically mean that active aspergillosis is present.

Assessment may involve:

symptoms and their pattern over time
CT imaging
Aspergillus-specific IgG or IgE
total IgE and eosinophils
sputum culture or PCR
lung-function testing
occasionally bronchoscopy

What about asthma and other lung diseases?

Asthma can also cause wheeze, cough and variable airflow obstruction. Some people have features of both asthma and COPD, particularly later in life. Asthma may also coexist with bronchiectasis.

Other conditions can produce similar symptoms, including:

interstitial lung disease
previous tuberculosis
heart failure
lung cancer
pulmonary hypertension
non-tuberculous mycobacterial infection
chronic pulmonary aspergillosis

This is why a diagnosis may need to be reconsidered when symptoms, scans or test results do not fit the original explanation.

Why might doctors change the diagnosis?

Doctors sometimes appear to switch between diagnoses such as COPD, asthma, bronchiectasis and aspergillosis. This can happen because the conditions share many symptoms, and because more than one condition may be present at the same time.

Early in an assessment, a doctor may use a working diagnosis based on the information available. That diagnosis may be refined when spirometry, CT scans, sputum tests or blood tests provide more evidence.

For example:

a person initially thought to have COPD may later be found to have bronchiectasis on CT
someone diagnosed with asthma may later develop persistent airflow obstruction or emphysema
a person with bronchiectasis may be found to have an underlying immune problem or previous infection
Aspergillus-related disease may become apparent when symptoms persist despite usual treatment

A changing diagnosis does not necessarily mean that earlier care was misguided. It may mean that the clinical picture has become clearer.

Can poor treatment response suggest another diagnosis?

Sometimes. If symptoms do not improve as expected, doctors may ask:

Was the original diagnosis correct?
Is another condition present as well?
Is there an infection or complication?
Is the treatment being taken correctly and tolerated?
Has the disease changed over time?

For example, someone repeatedly treated for COPD exacerbations who continues to produce large amounts of sputum may need assessment for bronchiectasis, chronic infection or Aspergillus-related disease.

However, lack of improvement does not prove that the diagnosis was wrong. Treatment may have been insufficient, difficult to take, affected by another medicine or aimed at only one part of a complex condition.

The most useful response is usually reassessment rather than an automatic change of label.

Why identifying the full picture matters

Different diagnoses lead clinicians to look for different problems and choose different treatments.

COPD may require bronchodilators, pulmonary rehabilitation and exacerbation prevention.
Bronchiectasis may require airway clearance, sputum monitoring and investigation of its cause.
Asthma may require treatment aimed at variable airway inflammation.
Aspergillus-related disease may require specific blood tests, microbiology or antifungal treatment.

Recognising one diagnosis does not exclude another. The aim is to understand all the factors contributing to a person’s symptoms.

Key message: COPD, bronchiectasis, asthma and aspergillosis can overlap, but they are not interchangeable diagnoses. Lung function shows how well the lungs work, while CT scans show structural damage. When symptoms persist or treatment is not working as expected, reassessing the diagnosis may reveal another condition—or several conditions acting together.

Related information

What is bronchiectasis?

Bronchiectasis is a long-term lung condition in which one or more airways become permanently widened, thickened or scarred.

Healthy airways use a thin layer of mucus and tiny hair-like structures called cilia to remove dust, microbes and other particles. In bronchiectasis, damaged airways often clear mucus less effectively. Mucus can collect in widened parts of the airway, allowing bacteria and fungi to remain in the lungs for longer.

Bronchiectasis may develop after:

severe or repeated chest infections
tuberculosis or other lung infections
immune-system problems
asthma or allergic bronchopulmonary aspergillosis
cystic fibrosis or primary ciliary dyskinesia
autoimmune or inflammatory conditions
airway blockage or inhaled foreign material

Sometimes no clear cause is found.

Common symptoms include:

a long-term cough
regular production of sputum
repeated chest infections
breathlessness
wheezing
fatigue
coughing up blood

Find out more about mucus clearance and airway-clearance techniques.

Why can bronchiectasis increase the risk of aspergillosis?

Bronchiectasis changes the structure of the airways and makes it harder to remove mucus. This may allow Aspergillus spores to remain in the airways and interact with the immune system.

The risk of Aspergillus-related disease may be influenced by:

the extent and location of bronchiectasis
how much mucus is retained
the number and severity of chest infections
underlying asthma or allergy
previous tuberculosis or other structural lung disease
corticosteroid or other immunosuppressive treatment
the individual immune response to Aspergillus

Aspergillus may be present in sputum without causing active disease. This is sometimes described as colonisation or airway carriage. Other people develop an exaggerated allergic response, Aspergillus bronchitis or a chronic fungal infection.

Different Aspergillus-related conditions

Several different Aspergillus-related conditions can occur in people with bronchiectasis. They should not be treated as if they are all the same.

Aspergillus sensitisation

Aspergillus sensitisation means that the immune system has developed an allergic response to Aspergillus. It may be associated with wheezing, airway inflammation or more frequent exacerbations, but it is not the same as an active fungal infection.

Allergic bronchopulmonary aspergillosis

Allergic bronchopulmonary aspergillosis (ABPA) occurs when the immune system reacts strongly to Aspergillus in the airways. It is traditionally associated with asthma and cystic fibrosis, but it can also occur in people with bronchiectasis who do not have either condition.

ABPA may cause:

worsening wheeze or breathlessness
thick or difficult-to-clear mucus
recurrent chest symptoms
increased eosinophils or IgE
fleeting or changing shadows on chest imaging
central bronchiectasis or high-attenuation mucus on CT

Read more about allergic bronchopulmonary aspergillosis.

Aspergillus bronchitis

Aspergillus bronchitis is a condition in which Aspergillus is repeatedly detected in the airways and is associated with a persistent productive cough, sputum and airway inflammation.

It is more likely to be considered when a person has:

a chronic productive cough
repeated detection of Aspergillus in sputum or bronchoscopy samples
an increased Aspergillus IgG level
no clear evidence of ABPA or CPA

Learn more in our guide to Aspergillus bronchitis.

Chronic pulmonary aspergillosis

Chronic pulmonary aspergillosis (CPA) is a long-term fungal infection that usually develops in structurally abnormal lungs. It may cause cavities, nodules, thickening around cavities or progressive changes over time.

Symptoms may include:

persistent cough
increasing breathlessness
weight loss
fatigue
night sweats or a low-grade fever
persistent sputum
coughing up blood

Read more about the different types of CPA.

What does recent research show?

A 2025 review examined ABPA and other Aspergillus-related airway diseases in bronchiectasis. It concluded that ABPA, Aspergillus sensitisation, chronic Aspergillus infection and Aspergillus bronchitis may form a spectrum of disease influenced by both airway damage and the immune response.

The review estimated that ABPA affects approximately 4% of people with bronchiectasis, although estimates vary substantially between studies and populations. It also reported that Aspergillus sensitisation and chronic Aspergillus infection may collectively affect up to 30% of people with bronchiectasis.

These figures should be interpreted cautiously. They do not mean that one in three people with bronchiectasis has an active fungal infection. Sensitisation, colonisation and active disease are different findings, and not everyone with a positive test requires antifungal treatment.

The review argued that Aspergillus-related disease may be associated with more severe bronchiectasis and more frequent exacerbations. It also noted that ABPA may sometimes contribute to bronchiectasis, rather than simply occurring as a result of already damaged airways.

A separate 2026 international study found that sensitisation to particular Aspergillus allergens was associated with markers of higher-risk bronchiectasis, including exacerbations, hospital admissions and Pseudomonas aeruginosa infection. The study does not prove that sensitisation causes bronchiectasis, but it suggests that fungal sensitisation may identify a subgroup needing closer assessment.

Can ABPA cause bronchiectasis?

The relationship between ABPA and bronchiectasis is complex.

Bronchiectasis may make it easier for Aspergillus to remain in the airways, increasing the opportunity for an allergic immune response. However, repeated Aspergillus-driven inflammation in ABPA may also damage the airways and contribute to bronchiectasis.

Recent research suggests that ABPA may contribute to bronchiectasis in some susceptible people, particularly when there is prolonged allergic inflammation and mucus plugging. However, not every person with ABPA develops bronchiectasis, and not every person with bronchiectasis has ABPA.

Symptoms can overlap

Bronchiectasis and Aspergillus-related disease may all cause:

cough
breathlessness
wheeze
fatigue
increased sputum
repeated chest infections
reduced exercise tolerance

This overlap can make it difficult to know whether symptoms represent a usual fluctuation, a bacterial infection, ABPA, Aspergillus bronchitis, CPA or a combination of conditions.

Further assessment may be useful when symptoms are unusually persistent, severe or different from previous exacerbations.

How might doctors investigate Aspergillus-related disease?

Assessment usually combines several types of information:

symptoms and their pattern over time
the frequency and severity of exacerbations
chest X-rays and CT scans
sputum cultures and other microbiology
Aspergillus-specific IgE and IgG blood tests
total IgE and eosinophil counts
lung-function testing
occasionally bronchoscopy

Aspergillus-specific IgG may support a diagnosis of CPA or Aspergillus bronchitis. Aspergillus-specific IgE and total IgE are more relevant when ABPA is suspected.

A positive blood test does not automatically prove active disease. Test results need to be interpreted with symptoms, imaging and sputum findings.

Why CT scans are important

CT scans can show the pattern and extent of bronchiectasis and may identify additional findings such as:

mucus plugging
high-attenuation mucus
nodules
cavities
thickening around cavities
changes suggesting a fungal ball

A CT scan may help distinguish established bronchiectasis from new changes that require further investigation. Read more about CT scans and aspergillosis.

When should someone with bronchiectasis seek further assessment?

Speak to your healthcare team if you have bronchiectasis and develop:

a clear change in your usual cough or sputum
repeated exacerbations or chest infections
symptoms that do not respond as expected to antibiotics
new or worsening wheeze
unexplained weight loss or fatigue
new changes on a chest X-ray or CT scan
repeated courses of steroids
coughing up blood

These symptoms do not necessarily mean that you have aspergillosis. They may be caused by bronchiectasis, bacteria, viruses, asthma or other conditions. The purpose of further assessment is to identify the cause accurately.

How is treatment decided?

Treatment depends on which Aspergillus-related condition is present.

Aspergillus sensitisation may require monitoring and treatment of associated airway disease rather than antifungal medication.
ABPA may require corticosteroids, antifungal treatment or other specialist therapies.
Aspergillus bronchitis may be considered for antifungal treatment when symptoms and microbiology support the diagnosis.
CPA may require prolonged antifungal treatment and careful monitoring.

Airway clearance, vaccination, treatment of bacterial infections and management of the underlying bronchiectasis remain important regardless of whether Aspergillus is detected.

Antifungal medicines can interact with inhalers, corticosteroids and other medicines, so they should only be started under appropriate medical supervision.

Key message: Bronchiectasis makes it harder to clear mucus and inhaled particles, which may increase vulnerability to several Aspergillus-related conditions. Most people with bronchiectasis will not develop active aspergillosis, but persistent or unusually severe symptoms may justify assessment for Aspergillus sensitisation, ABPA, Aspergillus bronchitis or CPA.

Related information

What is COPD?

Chronic obstructive pulmonary disease (COPD) is a long-term condition in which airflow through the lungs becomes restricted. The obstruction usually develops gradually and may become more noticeable over time.

COPD mainly includes two overlapping types of lung damage:

Chronic bronchitis: long-term inflammation of the airways, often with increased mucus production and a persistent cough.
Emphysema: damage to the small air sacs in the lungs, reducing the area available for oxygen to pass into the blood.

Many people have features of both. COPD can also cause narrowing of the smaller airways, trapping of air and difficulty clearing mucus from the lungs.

Symptoms may include:

breathlessness, especially during activity
a persistent cough
regular production of sputum
wheezing or chest tightness
repeated chest infections
reduced exercise tolerance
fatigue

Symptoms may remain fairly stable for long periods, but can suddenly worsen during an exacerbation. An exacerbation may be triggered by a viral or bacterial infection, air pollution, smoke, cold weather or other factors.

COPD is not contagious. It is also not simply an inevitable part of getting older. Diagnosis usually involves a medical history, examination and breathing tests such as spirometry.

What is aspergillosis?

Aspergillosis describes several different conditions caused by Aspergillus, a common mould found in soil, dust, compost and the air.

Most people breathe in Aspergillus spores without becoming ill. Problems are more likely when a person has damaged lungs, an altered immune response or treatment that suppresses immunity.

Relevant forms of disease include:

chronic pulmonary aspergillosis (CPA)
aspergilloma, sometimes called a fungal ball
Aspergillus bronchitis
allergic bronchopulmonary aspergillosis (ABPA)
invasive pulmonary aspergillosis

These conditions are different and require different investigations and treatments.

Why can COPD increase the risk of aspergillosis?

COPD can affect the lungs in several ways that may increase vulnerability to Aspergillus:

damaged airways may clear mucus and inhaled particles less effectively
emphysema can create areas of structurally abnormal lung
previous infections may leave scars or cavities
repeated exacerbations can increase inflammation and lung damage
corticosteroid treatment can alter the immune response

The risk is not caused by COPD alone. It depends on the severity and type of lung damage, previous infections, smoking history, immune function, steroid exposure and other health conditions.

New research: Aspergillus allergy and sensitisation in COPD

A 2026 systematic review and meta-analysis examined allergic bronchopulmonary aspergillosis (ABPA) and Aspergillus sensitisation in people with COPD. The researchers combined evidence from 23 studies involving more than 5,000 people.

They estimated that:

approximately 2.1% of people with COPD had ABPA
approximately 10.4% had evidence of sensitisation to Aspergillus

These findings suggest that Aspergillus-related allergy may occur in COPD more often than previously recognised. However, sensitisation is not the same as active infection or ABPA. A positive allergy or blood test does not automatically mean that treatment is needed.

The findings support a more careful assessment of people with COPD who have unexplained wheezing, difficult-to-control symptoms, recurrent exacerbations or features suggesting an allergic fungal response.

Read our summary of the 2026 COPD and Aspergillus review.

Chronic pulmonary aspergillosis and COPD

CPA is a long-term fungal lung infection that usually develops in areas of existing lung damage. It may cause cavities, thickening around cavities, nodules or progressive changes in the lungs.

Symptoms of CPA can include:

persistent cough
increasing breathlessness
fatigue
weight loss
night sweats or a low-grade fever
persistent or increasing sputum
coughing up blood

These symptoms can also occur during COPD exacerbations, which makes diagnosis difficult. Symptoms that continue after the usual treatment for a COPD flare-up may need further investigation.

Could Aspergillus be contributing to repeated COPD flare-ups?

Not every COPD exacerbation is caused by Aspergillus. Bacteria, viruses, pollution, smoking, weather changes and other factors can all trigger worsening symptoms.

However, Aspergillus may sometimes be involved when a person has:

frequent or unusually severe exacerbations
symptoms that do not respond as expected to antibiotics or inhalers
persistent chest symptoms between exacerbations
unexplained weight loss or fatigue
new cavities, nodules or other changes on a CT scan
recurrent haemoptysis
a history of tuberculosis or another condition causing structural lung damage

Research has also found Aspergillus in the airways of some people with COPD without proving that it is causing active disease. Detection of Aspergillus therefore needs to be interpreted alongside symptoms, imaging and other test results.

Why steroids need careful balancing

Corticosteroids may be prescribed during COPD exacerbations and, in some people, as part of regular inhaled treatment. They can reduce airway inflammation and improve symptoms.

However, corticosteroids can also affect the immune response that helps control Aspergillus. Recent research has reported an association between corticosteroid exposure and pulmonary aspergillosis, with higher exposure associated with greater risk.

This does not mean that people with COPD should stop their inhalers or avoid steroids when they are medically necessary. Treatment should only be changed with advice from a healthcare professional.

The important point is that repeated or prolonged steroid treatment, particularly when symptoms are not improving as expected, may be one reason to review the diagnosis and consider whether fungal disease or another infection is contributing. Read more about steroids, aspergillosis and the immune system.

How might doctors investigate aspergillosis?

There is no single test that diagnoses every form of aspergillosis. Assessment may include:

symptoms and how long they have been present
previous chest imaging and a current CT scan
lung-function testing
Aspergillus-specific IgG blood testing
total IgE and Aspergillus-specific IgE when ABPA is suspected
sputum culture, PCR or other microbiology
occasionally bronchoscopy

An Aspergillus IgG blood test can provide evidence of a longer-term immune response to Aspergillus and is often useful when CPA is being considered. However, a positive result does not prove active CPA by itself.

CT scans may help identify cavities, nodules, fibrosis, emphysema, mucus plugging or other changes that are difficult to see on a chest X-ray. Read more about why CT scans are used in aspergillosis.

When should someone with COPD seek further assessment?

Speak to your healthcare team if you have COPD and develop:

breathlessness that is worsening or different from usual
a cough that does not settle after an exacerbation
persistent or increasing sputum
unexplained weight loss or fatigue
repeated courses of antibiotics or steroids
new abnormalities on a chest X-ray or CT scan
coughing up blood

These symptoms do not necessarily mean that you have aspergillosis. They may result from COPD itself, infection, heart disease, medication effects or other causes. The purpose of further assessment is to identify the cause accurately so that treatment can be chosen appropriately.

Key message: Most people with COPD will not develop aspergillosis. However, COPD-related lung damage, repeated exacerbations and corticosteroid exposure may increase susceptibility. If symptoms are unusually persistent, severe or difficult to explain, Aspergillus-related disease may need to be considered alongside the more common causes of COPD deterioration.

Related information

What is sarcoidosis?

Sarcoidosis is an inflammatory condition in which groups of immune cells form small areas of inflammation called granulomas. It can affect several parts of the body, but the lungs and lymph nodes in the chest are most commonly involved.

Some people have few or no symptoms. Others may experience:

breathlessness
a persistent cough
chest discomfort
fatigue
reduced exercise tolerance
weight loss or a general feeling of being unwell

In some people, inflammation settles without causing permanent damage. In others, long-term inflammation can lead to scarring and changes in the structure of the lungs.

Why can sarcoidosis increase the risk of aspergillosis?

Chronic pulmonary aspergillosis (CPA) is a long-term lung infection caused by Aspergillus, a mould that is commonly found in the environment and is breathed in regularly by most people. You can read more about the different forms of CPA.

Healthy lungs usually clear inhaled Aspergillus spores without difficulty. However, damaged or scarred lung tissue can make it easier for Aspergillus to persist and grow.

Advanced pulmonary sarcoidosis may cause:

fibrosis and scarring
distortion of the airways
areas of poorly functioning lung
cavities or spaces within the lungs

These changes may create conditions in which chronic pulmonary aspergillosis or an aspergilloma can develop. An aspergilloma, sometimes called a fungal ball, is a collection of fungal material that grows within an existing lung cavity.

The risk is not caused by sarcoidosis alone. It reflects a combination of factors, including the amount and type of lung damage, the immune response, exposure to Aspergillus and treatments such as corticosteroids or other immunosuppressive medicines.

How common is the association?

The relationship between sarcoidosis and chronic pulmonary aspergillosis is clinically important, but it remains relatively understudied. A 2026 review reported that approximately 2% of people with sarcoidosis developed CPA in some recent tertiary-care cohorts.

Older studies involving people with more advanced fibrocystic sarcoidosis reported higher estimates, between 3% and 12%. These figures are not directly comparable because specialist centres tend to see more people with severe and complicated disease.

The available evidence does not suggest that sarcoidosis commonly or inevitably leads to aspergillosis. Instead, risk appears to result from several factors acting together:

fibrosis, cavities or other structural lung damage
changes in local and general immune function
regular exposure to Aspergillus in the environment
corticosteroid or other immunosuppressive treatment

Symptoms can overlap

One of the difficulties is that sarcoidosis and chronic pulmonary aspergillosis can cause similar symptoms. These may include:

increasing breathlessness
persistent or worsening cough
fatigue
weight loss
reduced lung function
declining ability to exercise
changes visible on chest X-rays or CT scans

This overlap can make it difficult to tell whether symptoms are caused by active sarcoidosis, permanent lung damage, chronic infection, or more than one condition at the same time.

Blood in the sputum, known as haemoptysis, can occur with several lung conditions. It may also occur when an aspergilloma or CPA affects blood vessels in damaged lung tissue. Any new or significant haemoptysis should be discussed promptly with a healthcare professional.

Why scans may need careful interpretation

Chest imaging is an important part of assessing both sarcoidosis and aspergillosis. A CT scan may show fibrosis, nodules, cavities, thickening around cavities or changes in existing areas of lung damage.

Some of these findings can be seen in advanced sarcoidosis as well as CPA. A single scan does not always provide the complete answer. Doctors may need to compare scans over time and consider:

whether existing cavities or scars are changing
whether new cavities or nodules have appeared
whether there is thickening around a cavity
whether a fungal ball is present
how scan findings relate to symptoms and lung-function results

The overall pattern, and how it changes over time, is often more useful than one isolated scan finding. Read more about why CT scans are used in aspergillosis.

The challenge of steroid treatment

Corticosteroids are often used to control inflammation caused by sarcoidosis. Other immunosuppressive medicines may also be used when sarcoidosis affects the lungs or other organs.

These treatments can be very important and should not be stopped suddenly or changed without medical advice. However, corticosteroids and some other immunosuppressive medicines can reduce the body's ability to control infection.

If chronic pulmonary aspergillosis is present but not recognised, increasing immunosuppression may allow the infection to become more active. This is one reason why unexpected deterioration, new radiological changes or symptoms that do not respond as expected should be assessed carefully before assuming that sarcoidosis is the only cause.

This does not mean that steroids are always unsafe for people with sarcoidosis. The decision is individual and may involve balancing inflammation, infection risk, lung damage and other health needs. Read more about steroids, aspergillosis and the immune system.

What does recent research show?

A 2026 review concluded that CPA occurs mainly when sarcoidosis has caused substantial structural lung damage, particularly fibrosis or cavities. The authors described the association as clinically important but relatively understudied.

In a study of 65 people with CPA complicating sarcoidosis, almost all had advanced fibrocystic pulmonary disease. Chronic cavitary pulmonary aspergillosis was the most common form of CPA. The factors most strongly associated with outcome were the extent of fibrosis, reduced overall lung function and pulmonary hypertension.

The study also found that poor outcomes were more often related to advanced sarcoidosis and the resulting loss of lung function than to aspergillosis alone. This is important because it shows that CPA is part of a complex picture rather than necessarily being the only cause of deterioration.

These findings help explain why assessment needs to consider the whole clinical picture. A change in symptoms or a scan may reflect active sarcoidosis, permanent lung damage, CPA or a combination of these conditions.

How might doctors investigate aspergillosis?

There is no single test that diagnoses every form of aspergillosis. Doctors usually combine several types of information, including:

symptoms and how they have changed
previous CT scans and current imaging
lung-function tests
blood tests for Aspergillus-specific antibodies, particularly Aspergillus IgG
sputum testing for Aspergillus and other organisms
occasionally bronchoscopy or other specialised tests

Blood tests for Aspergillus-specific IgG may support the diagnosis of CPA. However, a positive result does not prove by itself that active infection is present. It must be interpreted alongside symptoms, imaging and other test results.

Doctors may also use sputum testing, lung-function tests and, occasionally, bronchoscopy. Read more about how aspergillosis is diagnosed.

The 2026 review emphasised that diagnosis usually depends on combining imaging, Aspergillus-specific IgG and microbiological evidence with evidence of clinical progression.

Why specialist review may be helpful

Managing sarcoidosis and CPA together can be complicated. Treatment for sarcoidosis may involve corticosteroids or other medicines that suppress inflammation, while CPA may require prolonged antifungal treatment.

These medicines can interact with each other, and antifungal treatment may require monitoring for side effects, liver problems and drug levels. Some patients may need long-term antifungal treatment, particularly if disease is progressive or returns after treatment is stopped.

For this reason, unexpected deterioration, new cavities, progressive changes on CT, persistent systemic symptoms or haemoptysis may require discussion between respiratory, sarcoidosis and fungal-disease specialists.

What does this mean for someone with sarcoidosis?

Having sarcoidosis does not mean that you will develop aspergillosis. The association is most relevant in people with significant structural lung damage, particularly fibrosis or cavities.

It is worth telling your healthcare team if you develop:

new or worsening breathlessness
a persistent change in your cough
unexplained weight loss or worsening fatigue
repeated chest infections
new changes on a chest X-ray or CT scan
coughing up blood
symptoms that continue despite treatment for sarcoidosis

These symptoms can have many causes, and they do not necessarily mean that you have aspergillosis. They simply deserve appropriate assessment rather than being automatically attributed to sarcoidosis.

Key message: Sarcoidosis and aspergillosis are separate conditions, but advanced sarcoidosis can sometimes cause lung changes in which chronic pulmonary aspergillosis develops. Most people with sarcoidosis will not develop CPA. When symptoms or scans change unexpectedly, considering both inflammation and infection can help doctors choose the safest treatment.

Related information

What is pulmonary tuberculosis?

Tuberculosis (TB) is an infection caused by bacteria belonging to the Mycobacterium tuberculosis group. It can affect several parts of the body, but pulmonary TB affects the lungs.

Active pulmonary TB can cause inflammation and destroy areas of lung tissue. Treatment can remove the active bacteria, but it cannot always reverse the structural damage that has already occurred.

Changes remaining after treatment may include:

scarring and fibrosis;
persistent spaces or cavities within the lungs;
bronchiectasis, in which damaged airways become widened;
thickening of the lining around the lungs;
reduced lung volume or distortion of the airways;
impaired mucus clearance.

These changes are collectively described as part of post-tuberculosis lung disease. They can cause long-term symptoms even when no active TB bacteria remain.

How can previous TB lead to aspergillosis?

Aspergillus is a common mould found in soil, compost, dust and the air around us. Most people inhale its microscopic spores regularly without becoming ill.

A healthy lung usually clears the spores effectively. However, a cavity left by pulmonary TB provides an abnormal space in which Aspergillus may settle and grow.

This can lead to several different problems:

Aspergilloma: a fungal ball that forms inside an existing lung cavity.
Chronic cavitary pulmonary aspergillosis: one or more cavities that persist or gradually enlarge, sometimes containing a fungal ball.
Chronic fibrosing pulmonary aspergillosis: extensive scarring and destruction that can develop when chronic disease progresses.
Aspergillus nodules: one or more rounded abnormalities that may resemble cancer or another infection on a scan.

These forms sit within the spectrum known as chronic pulmonary aspergillosis.

Post-TB bronchiectasis may also impair mucus clearance and make the lungs more vulnerable to repeated bacterial or fungal infection.

Does everyone who has had TB need to worry?

No. Most people treated for TB will not develop CPA.

The risk is greater when pulmonary TB has left substantial structural damage, particularly one or more persistent cavities. Other factors may include:

bronchiectasis;
COPD or emphysema;
low body weight or poor nutrition;
diabetes;
immune suppression;
long-term or repeated corticosteroid treatment;
more than one episode of pulmonary TB.

Latent TB—where TB bacteria are present without active disease—does not usually produce the same lung cavities and is not equivalent to having had destructive pulmonary TB.

Why are TB and CPA easily confused?

The two conditions share several possible symptoms:

a persistent cough;
increasing breathlessness;
fatigue;
weight loss or difficulty regaining weight;
fever or night sweats;
chest discomfort;
coughing up blood (haemoptysis).

Both can also produce cavities, scarring and areas of inflammation on chest X-rays or CT scans.

When symptoms recur after TB treatment, it is therefore understandable that recurrent TB may be suspected first. In countries where TB is common but fungal diagnostic tests are difficult to obtain, some people may receive further courses of anti-TB treatment without convincing evidence that active TB has returned.

However, TB medicines do not treat Aspergillus. Delayed recognition allows CPA to continue damaging the lungs.

Can active TB and aspergillosis occur together?

Yes. Although CPA often becomes apparent after TB treatment, active TB and Aspergillus-related disease can occasionally coexist.

Finding evidence of one condition therefore does not always exclude the other. Clinicians may need to investigate for both, particularly when:

symptoms or imaging do not improve as expected;
TB tests are repeatedly negative despite continuing symptoms;
the patient initially improves but then deteriorates;
there is a persistent cavity or a possible fungal ball;
significant coughing of blood develops.

Coexisting disease can make treatment more complicated. Rifampicin and some other TB medicines interact strongly with azole antifungal medicines, so treatment must be planned and monitored by clinicians experienced in managing these interactions.

When should CPA be considered after TB?

Further assessment may be appropriate when respiratory or constitutional symptoms persist for several months, return after treatment or gradually worsen—especially in someone with cavities or other substantial changes on lung imaging.

Symptoms warranting discussion with a healthcare professional include:

a cough that does not settle;
gradually worsening breathlessness;
ongoing or unexplained fatigue;
unintentional weight loss;
recurrent chest infections;
blood in the sputum;
new or enlarging cavities on imaging.

These symptoms have many possible causes. They do not prove that CPA is present, but they should not automatically be attributed to old TB damage without considering other explanations.

How is chronic pulmonary aspergillosis diagnosed?

There is no single test that diagnoses every case. Clinicians combine the person’s history, symptoms, imaging and laboratory results. You can find a broader explanation on our diagnosis of aspergillosis page.

Chest imaging

A CT scan provides much more detail than a chest X-ray. Features that may raise suspicion include:

one or more lung cavities;
a cavity that is enlarging or developing a thicker wall;
a fungal ball within a cavity;
thickening around the cavity or lining of the lung;
new areas of inflammation around an old cavity;
progressive fibrosis or loss of lung volume;
one or more nodules.

Comparison with older images is extremely valuable. A single abnormal scan may show the damage left by TB, but scans taken over time can reveal whether the disease is stable or progressing.

Aspergillus IgG blood testing

An Aspergillus IgG antibody test is one of the most useful blood tests for CPA. A positive result indicates that the immune system has made a significant response to Aspergillus.

The result must be interpreted alongside symptoms and imaging. A positive result alone does not prove active CPA, while a negative result does not exclude every case, particularly in someone whose immune system cannot produce a strong antibody response.

Sputum testing

Sputum may be tested using fungal culture or molecular techniques such as PCR. Finding Aspergillus supports the diagnosis, but cultures are often negative even when CPA is present.

A negative sputum culture should therefore not be used by itself to rule out CPA.

Sputum should also be tested for TB and, where appropriate, other bacteria or nontuberculous mycobacteria. More than one infection may be present.

Other investigations

Depending on the individual case, clinicians may use:

lung-function testing;
bronchoscopy and samples from the lower airways;
biopsy of a nodule or other abnormal area;
tests for other fungal infections found in particular parts of the world;
assessment for lung cancer or another cause of cavitation.

How is CPA treated?

Treatment depends on the form and severity of disease, the person’s symptoms, whether imaging is progressing and their other medical conditions.

Oral antifungal medicines such as itraconazole or voriconazole are commonly used. Posaconazole or isavuconazole may be considered in some circumstances. Treatment frequently continues for many months and sometimes longer.

Monitoring is important because antifungal medicines can:

interact with other medicines;
affect the liver or cause other adverse effects;
produce blood levels that are too low or too high;
be ineffective if the infecting Aspergillus is resistant.

Blood tests, antifungal drug-level measurements and follow-up imaging may therefore be required. Read more about drug interactions with antifungal medicines.

A single stable aspergilloma without significant symptoms may sometimes be monitored rather than treated immediately. Surgery may be considered in selected patients with a localised fungal ball and adequate lung function. Significant bleeding may require urgent treatment, including a procedure to block the responsible blood vessel.

Why does earlier recognition matter?

Untreated CPA can gradually enlarge lung cavities, increase fibrosis and further reduce lung function. It can also cause severe or recurrent bleeding.

Earlier diagnosis offers several potential benefits:

avoiding unnecessary repeat courses of TB medication;
starting appropriate antifungal treatment when needed;
monitoring cavities before extensive damage develops;
identifying other causes of persistent symptoms;
improving recognition of post-TB lung disease more broadly.

Not every person who has completed TB treatment needs extensive fungal testing. A more practical approach is to investigate people with persistent or recurrent symptoms, residual cavities or unexplained progression on imaging.

The global diagnostic gap

TB affects millions of people worldwide, particularly in countries where access to CT scanning, Aspergillus IgG testing and specialist fungal services may be limited.

Recent research has confirmed a substantial burden of CPA among people previously treated for TB. However, estimates vary widely between studies because the populations, diagnostic tests and definitions differ.

This is not simply a problem in countries with a high TB incidence. People may move between countries many years after treatment, and CPA can emerge or be recognised long after the original infection.

A history of pulmonary TB remains clinically relevant even if treatment took place decades earlier.

Healthcare professionals can read our specialist evidence summary on CPA during tuberculosis treatment for a more detailed discussion of recent research and diagnostic pathways.

What should patients do?

If you have previously been treated for pulmonary TB and continue to experience respiratory symptoms:

tell your clinician about the previous TB, even if it occurred many years ago;
ask whether old and current scans have been compared;
ask whether cavities, bronchiectasis or substantial scarring remain;
discuss whether Aspergillus IgG and sputum testing would be appropriate;
seek prompt advice if you cough up blood;
do not stop or alter TB or antifungal medication without medical advice.

Coughing up more than a few streaks or spots of blood, or bleeding accompanied by breathlessness, dizziness or weakness, requires urgent medical assessment. Call emergency services if the bleeding is substantial.

For more detailed information about recognising and responding to bleeding, see our patient guide to haemoptysis.

Key points

Pulmonary TB can leave cavities, scarring and bronchiectasis even after the infection has been successfully treated.
These structural changes can increase susceptibility to chronic pulmonary aspergillosis.
TB and CPA can both cause cough, weight loss, fatigue, breathlessness, bleeding and lung cavities.
CPA may be mistaken for recurrent TB or dismissed as permanent post-TB damage.
Diagnosis usually requires a combination of CT imaging, Aspergillus IgG testing and microbiological evidence.
A negative sputum fungal culture does not exclude CPA.
Most people treated for TB do not develop CPA, but persistent or worsening symptoms deserve investigation.

Further information and evidence

This article provides general information and does not replace assessment by a TB, respiratory or fungal-infection specialist.

by GAtherton

Dehumidifier operating beside indoor laundry with a hygrometer showing 50% relative humidity.

Dehumidifiers: How to Reduce Damp, Condensation and Mould Safely

How to choose, use and clean a dehumidifier safely—and understand what it can and cannot do about damp and mould

Dehumidifiers can be useful when excess moisture is building up inside a home. They can reduce condensation, help laundry dry indoors and make it harder for mould to grow.

However, a dehumidifier is not a complete solution to every damp problem. It removes water from the air; it does not repair a leaking roof or pipe, stop rain entering through a wall, correct rising damp, insulate a cold surface or provide fresh air.

Quick answer

Use an inexpensive digital hygrometer to measure relative humidity.
A practical target for most homes is approximately 40–55% relative humidity.
Try to prevent humidity remaining above 60%, where condensation and mould become more likely.
Do not try to make the air extremely dry: prolonged humidity below about 30% may irritate the eyes, skin and airways.
Choose a unit appropriate for the room temperature and size—not simply the largest number printed on the box.
Empty and clean the water tank and filter regularly so that the appliance itself does not become contaminated.

Where does indoor moisture come from?
Find the cause before buying a dehumidifier
What humidity should I aim for?
When is a dehumidifier helpful?
Compressor, desiccant or mini dehumidifier?
How to choose a suitable model
How to use it effectively
Cleaning and preventing fungal growth
How to calculate the running cost
What does this mean for someone with aspergillosis?
If you rent your home

Where Does Indoor Moisture Come From?

Moisture is continually added to indoor air by ordinary activities, including:

breathing and perspiration
showering and bathing
cooking and boiling water
drying washing indoors
unvented tumble dryers
paraffin or portable bottled-gas heaters
aquariums and large numbers of houseplants
water entering through leaks or defects in the building

Warm air can contain more water vapour than cold air. When warm, moist air meets a cold window, outside wall or other cold surface, some of that water may condense. This is why dripping windows and mould in cold corners are often most noticeable during winter.

Find the Cause Before Buying a Dehumidifier

Different forms of damp require different solutions.

Likely problem	Typical clues	What is needed?
Condensation	Water on windows; mould in corners, behind furniture or on cold outside walls; worse during cold weather or after cooking, showering or drying laundry.	Reduce moisture production, improve ventilation and heating, address cold surfaces and consider a dehumidifier.
Penetrating damp or a leak	A localised wet patch, staining, damaged plaster or worsening after rain; possible leaking roof, gutter, pipe or window.	Repair the source of water. A dehumidifier may help the structure dry afterwards but cannot repair the fault.
Rising damp	Damp and salts low down on ground-floor or basement walls, sometimes with a visible tide mark.	Professional investigation and appropriate building repair.
Construction moisture	A new building, extension, plastering or other recent wet building work.	Time, appropriate heat and ventilation; a suitable dehumidifier may speed drying.

If water is entering the property, the priority is to stop it. Continuously operating a dehumidifier while a leak remains is like emptying a bath while leaving the tap running.

A dehumidifier does not replace ventilation. It removes water from existing indoor air but does not remove carbon dioxide, cooking pollutants, odours or other contaminants, and it does not bring fresh air into the home.

What Humidity Should I Aim For?

Relative humidity—usually shown as % RH—describes how much water vapour the air contains relative to the maximum it could contain at that temperature.

NHS advice recommends keeping indoor humidity between 40% and 60%. For a home with recurring condensation or for someone trying to reduce conditions favourable to mould, a practical operating target is often around 45–55%.

Repeatedly above 60%: investigate moisture production, ventilation, heating, cold surfaces and building defects.
Around 40–55%: a useful practical range for many occupied homes.
Below 30% for long periods: may be unnecessarily dry and can irritate airways, skin and eyes.

A small digital hygrometer is more useful than guessing. Place it away from radiators, windows, direct sunlight and the dehumidifier’s air outlet. If possible, move it between rooms or use more than one to identify where and when humidity rises.

Remember that relative humidity changes with temperature. A cold wall may still develop surface condensation even when the centre of the room appears acceptable.

When Is a Dehumidifier Helpful?

A dehumidifier may be useful:

when condensation persists despite reasonable heating and ventilation
in a basement or other area where effective ventilation is difficult
while drying laundry indoors, particularly when outdoor drying is impossible
after a leak or flood has been repaired
during humid weather when opening windows does not lower indoor humidity
as a temporary measure while a landlord or contractor investigates the underlying problem

On a dry day, opening windows and using extractor fans may remove moisture more cheaply while also improving air quality. On a very humid day, bringing outdoor air inside may not lower the humidity, so a hygrometer can help you judge what works.

A dehumidifier will not remove mould that is already growing. Existing mould and its underlying moisture source still need to be dealt with safely.

Compressor, Desiccant or Mini Dehumidifier?

Type	Usually best for	Important limitations
Compressor or refrigerant	Heated living spaces. These cool humid air so that water condenses into a tank.	Performance falls in colder rooms, and the unit may need to pause for defrosting. Usually heavier and contains refrigerant.
Desiccant	Cooler spaces such as an unheated room, garage, boat or conservatory. An absorbent material captures moisture.	Often uses more electricity, although the warm outlet air can be useful in a cold space.
Thermoelectric or Peltier mini unit	A very small enclosed space with a minor moisture problem.	Removes far less water than a full-sized unit and is unlikely to control serious room-scale condensation.
Disposable moisture absorber	A cupboard, wardrobe or similarly small enclosed space.	Not a substitute for an electric dehumidifier in a damp room or home. The collected liquid also needs careful handling.

For most normally heated UK bedrooms and living rooms, a compressor model is usually the starting point. A desiccant model may be more effective if the space is consistently cold.

How to Choose a Suitable Model

Do not rely on the advertised litres per day alone

Extraction figures are commonly measured under warm and very humid test conditions. A machine advertised as removing 12 or 20 litres per day will usually collect much less in an ordinary UK home, especially in a cooler room.

Use the manufacturer’s recommended room size as a starting point, but also consider how cold the space is, how severe the moisture problem is and whether you are trying to dry laundry. A very small machine may run continuously without ever reaching the target humidity.

Useful features

An adjustable humidistat: allows the unit to stop automatically when the chosen RH is reached.
Automatic restart: useful after a brief power interruption, where appropriate.
Automatic defrost: important for compressor units used in cooler rooms.
A washable or replaceable air filter: check how easily it can be removed and cleaned.
A visible tank and full-tank shut-off: reduces the risk of overflow.
Continuous drainage: useful if the unit will operate for long periods and a safe drain is available.
Appropriate noise level: particularly important for a bedroom or shared living space.
Clear power consumption: compare watts as well as the purchase price.
Laundry mode: useful, but normally means a higher fan speed and greater noise or electricity use.

Independent comparative testing can be more informative than the headline extraction figure because it may measure performance at both normal room temperature and colder conditions.

How to Use a Dehumidifier Effectively

Read the manufacturer’s instructions. Required clearances, operating temperatures and drainage arrangements differ between models.
Place it where air can circulate. Do not cover the inlet or outlet, press it against curtains or furniture, or put laundry directly over it.
Use the humidistat. Start at approximately 50–55% RH rather than running continuously at the driest possible setting.
Close windows and outside doors while actively dehumidifying a room. Otherwise, the machine may continually try to dry incoming outdoor air.
Contain high-moisture activities. When drying laundry, use a suitable room, close its internal door and follow the appliance’s safety instructions.
Continue to ventilate the home appropriately. Use bathroom and kitchen extractors and trickle vents to remove pollutants and moisture at source.
Keep the building reasonably and evenly heated. Warmer surfaces are less likely to collect condensation.
Move the unit only as instructed. Compressor models may need to remain upright for a period after transport before being switched on.

If one unit is being used for several rooms, it is often more effective to treat the worst room with the door closed and then move the unit, rather than expecting a small machine in a hallway to control an entire home.

Cleaning and Preventing Fungal Growth

A dehumidifier deliberately collects water and dust. If neglected, its tank or filter can become dirty and may support microbial growth.

Empty the tank whenever it is full and do not leave collected water standing unnecessarily.
Wash and dry the tank at the interval recommended by the manufacturer.
Clean the air filter regularly—some housing guidance recommends checking it weekly during frequent use.
Inspect the tank, float, drainage hose and accessible surfaces for slime, deposits or visible growth.
If using continuous drainage, make sure the hose falls correctly to a suitable drain and cannot develop stagnant loops of water.
Do not add fragrances, bleach, disinfectants or other chemicals to the tank unless the manufacturer specifically permits this.
Before storing the machine, clean it and allow the tank and accessible components to dry fully.

For people with aspergillosis or another chronic lung condition: if the machine smells musty, contains visible mould or has inaccessible contamination, avoid running it and blowing air through it. Ask someone else to clean it safely according to the instructions, or seek advice from the manufacturer.

How to Calculate the Running Cost

Electricity prices change, so a fixed “cost per day” quickly becomes inaccurate. You can calculate the approximate cost from the appliance’s power rating:

Power in watts ÷ 1,000 × hours used × your electricity price per kWh

For example, a 300-watt machine used for eight hours consumes up to:

300 ÷ 1,000 × 8 = 2.4 kWh

Multiply 2.4 by the price per kWh shown on your electricity tariff. A humidistat will usually reduce consumption once the target humidity is reached, so actual use may be lower than this maximum calculation.

Compare machines by how much useful water they remove under realistic conditions, not wattage alone. A low-powered but ineffective unit that runs continuously may not be the cheapest option.

What Does This Mean for Someone With Aspergillosis?

Damp and mould are associated with respiratory health problems, and people with existing respiratory disease may be more vulnerable to their effects. Reducing persistent dampness and preventing mould growth is therefore sensible.

However:

a dehumidifier does not treat aspergillosis
it does not remove fungal growth already present in a building
it cannot guarantee that airborne fungal exposure has been eliminated
there is not enough evidence to promise that buying one will improve an individual patient’s symptoms or prevent a relapse

Its role is practical: controlling excess indoor moisture when that is part of the problem.

People with significant lung disease should avoid personally disturbing large or extensive areas of mould. Dry brushing or sanding can release particles into the air. The moisture source and necessary remediation should be assessed, and appropriate professional help may be needed.

If You Rent Your Home

Do not allow a supplied dehumidifier to become the landlord’s only response to a leaking, structurally damp, poorly insulated or inadequately ventilated property.

Government guidance for England states that landlords should identify and address the underlying causes of damp and mould rather than dismissing the problem as the result of a resident’s “lifestyle”. Report problems in writing, keep photographs and dates, and record any effects on health or damage to belongings.

For social housing in England, the first phase of Awaab’s Law has applied since 27 October 2025 and covers emergency hazards and significant damp-and-mould hazards. Rights and procedures differ elsewhere in the UK and internationally, so use the housing guidance for your location.

A dehumidifier may be a useful temporary safety measure while investigation and repair take place. It should not transfer responsibility for a defective building to the tenant.

Summary

A dehumidifier can reduce excess moisture and condensation when it is correctly sized, correctly used and properly cleaned. Aim for a measured indoor relative humidity of approximately 40–55%, and investigate readings that remain above 60%.

The best long-term solution is always to control moisture at source: repair leaks, use effective extraction and ventilation, avoid unnecessary moisture production, provide appropriate heating and address cold or poorly insulated surfaces.

Control the moisture, but also find out why it is there.

Quick guide

Enjoy the garden, but reduce avoidable exposure.
Avoid turning compost heaps, shredding decaying vegetation, using leaf blowers and opening dusty compost bags yourself.
Never open or tip compost, bark, mulch or potting mix inside a greenhouse, shed or other enclosed space.
Ask someone else to do the dustiest jobs whenever possible.
If exposure cannot be avoided, use a well-fitting certified respirator—preferably FFP3 for high levels of mould spores—and understand its limitations.
Wear gloves, cover cuts, wash your hands and change dusty clothing afterwards.
If you are severely immunocompromised, ask your specialist team whether you should avoid soil and compost completely during the high-risk period.

Why can gardening create an exposure?
Does everyone with aspergillosis need the same precautions?
Which gardening jobs create the most exposure?
Lower-exposure ways to enjoy gardening
Compost, potting mix, mulch and bark
Choosing and using a mask
Before, during and after gardening
Greenhouses, sheds and enclosed spaces
What about pollen and asthma?
When should I seek medical advice?

Why Can Gardening Create an Exposure?

Aspergillus species occur naturally throughout the environment. They help break down dead plant material and are particularly associated with soil, compost, leaf litter, stored vegetation and other decomposing organic matter.

The fungus produces microscopic airborne spores. We all breathe some spores during everyday life, and completely avoiding them is impossible. Exposure can rise sharply, however, when contaminated material is disturbed.

Examples include:

opening and tipping a bag of compost
turning a warm compost heap
sweeping a dry shed or greenhouse
shredding leaves or woody garden waste
using a leaf blower
moving damp or mouldy bark, mulch or wood chips
handling decaying plants

The concern is inhalation rather than simply touching an ordinary healthy plant. The amount released varies greatly with the material, moisture, temperature, weather, ventilation and how vigorously it is disturbed.

Compost is also one of the environmental settings in which azole-resistant Aspergillus fumigatus has been detected. This is another reason to reduce intense compost exposure, but it does not mean that every compost bag contains resistant fungus or that a single gardening session will cause infection.

Does Everyone With Aspergillosis Need the Same Precautions?

No. “Aspergillosis” includes several different illnesses, and people’s immune systems, lungs, treatments and gardening activities differ.

Situation	How to think about gardening
Aspergillus allergy, asthma or ABPA	Dust, fungal particles and pollen may provoke airway symptoms. Concentrate on avoiding visible dust and high-spore tasks and make sure asthma treatment is well controlled.
CPA, bronchiectasis or another chronic lung condition	There is no precise exposure threshold known to be safe or harmful. Reducing concentrated exposure is sensible, while adapted lower-exposure gardening may remain valuable.
Severely weakened immune system	People who are neutropenic, receiving certain chemotherapy or transplant treatments, or otherwise at high risk of invasive aspergillosis may be advised to avoid gardening, soil, compost and dusty outdoor work. Follow the specialist team’s advice.
Taking corticosteroids or other immune-modifying treatment	Risk depends on the medicine, dose, duration and the rest of your health. Do not assume that every steroid inhaler creates the same risk as high-dose systemic immunosuppression; ask the clinical team if uncertain.

If your immune status has recently changed—for example, following transplantation, chemotherapy, a major increase in systemic steroid treatment or a very low white-cell count—check whether your previous gardening routine remains appropriate.

Protective measures reduce exposure; they cannot make a high-exposure activity completely risk-free. The more vulnerable the person, the more important avoidance and delegation become.

Which Gardening Jobs Create the Most Exposure?

Consider asking someone else to do the following:

turning or emptying a compost heap or bin
opening, tipping or mixing bagged compost, manure, bark or mulch
shredding or chipping garden waste
handling heaps of dead leaves, grass clippings or rotting vegetation
using a leaf blower or dry power sweeper
mowing very dry grass, particularly if grass or pollen triggers symptoms
cleaning a dusty or mouldy greenhouse, shed or plant pot store
moving mouldy wood, hay, straw or stored bulbs
pressure-washing or dry-brushing visibly mouldy surfaces

Distance matters. If someone else is doing one of these jobs, do not stand nearby. Stay upwind and allow airborne dust to settle before returning.

Dry and windy conditions make dust harder to control. Waiting for calmer weather or lightly dampening dry soil before someone works on it may reduce dust, although it will not remove fungal spores or make mouldy material safe.

Lower-Exposure Ways to Enjoy Gardening

Many activities involve little or no disturbance of compost or decaying matter. Depending on your mobility and respiratory health, possibilities include:

watering established plants
dead-heading healthy flowers before material begins to decay
light pruning of healthy plants
planning planting schemes or choosing plants
harvesting fruit, vegetables or herbs from established plants
using raised beds to reduce bending and effort
working with someone else who handles soil and compost
buying pre-planted containers rather than filling pots yourself
photography, birdwatching or simply spending time in the garden

A “no-dig” approach may reduce repeated soil disturbance, although the compost or mulch used to establish it should be handled and spread by someone else.

Gardening can still be physically demanding. Pace activity, use lightweight or long-handled tools, sit for suitable tasks and take rests before breathlessness becomes severe. Pulmonary rehabilitation principles—gradual activity, pacing and breathing control—can be useful in the garden too.

Compost, Potting Mix, Mulch and Bark

Commercial bags are not sterile. Compost and related materials may contain fungi even when they look normal and carry no visible mould.

If possible, ask someone else to:

open bags outdoors
stand upwind while opening or pouring them
avoid squeezing a sealed bag and forcing dusty air towards the face
tip the material gently rather than from a height
prepare pots before you enter the area
close or cover unused material and store it outside living areas

Never open compost inside the home, greenhouse, conservatory, garage or shed. Enclosed spaces allow released particles to become concentrated and remain in the air.

Homemade compost heaps are particularly active biological environments. Adding kitchen or garden waste from a distance is less disturbing than turning, sieving or emptying the heap, but a severely immunocompromised person may be advised to avoid the area entirely.

Choosing and Using a Mask

A loose surgical mask, fabric face covering or single-strap “nuisance dust mask” is not designed to provide reliable protection from fine airborne dust and mould spores.

Use a certified filtering respirator marked to the appropriate standard. In the UK, disposable respirators should carry the relevant conformity marking and EN 149 classification.

FFP2: may reduce inhalation during lower-level dusty tasks when it fits correctly.
FFP3: provides a higher level of filtration and is advised by the Health and Safety Executive for high levels of mould spores.

The stated protection is only achieved when the respirator seals properly to the face.

Follow the manufacturer’s fitting instructions.
Check the seal every time it is worn.
A beard or heavy stubble prevents a tight seal on most disposable respirators.
Replace a disposable respirator if it becomes damp, damaged, dirty or difficult to breathe through.
Do not touch the contaminated outside unnecessarily.
Do not store a used disposable respirator in a dusty shed for repeated use.

A respirator can feel hot and may increase the sensation of breathing effort. If you have severe lung disease, discuss suitable respiratory protection with your clinical team. A reusable or powered option may sometimes be more appropriate, but it also requires correct selection, cleaning and maintenance.

A mask is the last line of protection, not the first. Avoiding or delegating a high-spore task is more reliable than using a mask to make the task appear completely safe.

Before, During and After Gardening

Before

Check whether the planned job involves compost, decaying plants or visible dust.
Choose a calm day and avoid the hottest part of the day if heat worsens breathlessness.
Make sure prescribed inhalers and any agreed respiratory action plan are available.
Cover cuts and broken skin with a waterproof dressing.
Wear gloves, closed shoes and clothing that covers exposed skin for soil-related work.
Use eye protection when pruning thorny plants, using powered tools or where debris may fly.

During

Work upwind of any dust source.
Avoid touching the face or adjusting the respirator with dirty gloves.
Stop if you become unusually wheezy, tight-chested, dizzy or breathless.
Do not push through severe symptoms simply to finish a job.

After

Remove dusty shoes and outer clothing before entering the main living space.
Wash hands and exposed skin thoroughly.
Clean any scratches or puncture wounds promptly with soap and water.
Shower and wash hair after a particularly dusty exposure if practical.
Keep visibly dusty work clothing separate until it can be washed.
Clean reusable protective equipment according to its instructions.

Plant thorns and sticks can injure the eye and, rarely, introduce fungi. Seek prompt assessment for eye pain, redness, sensitivity to light or blurred vision following a gardening injury.

Greenhouses, Sheds and Enclosed Spaces

A greenhouse or shed can accumulate dust, decaying leaves, old compost and mouldy wood. Because the air volume is small and ventilation may be poor, disturbing this material can create a more concentrated exposure than doing the same task outdoors.

Ventilate the space fully before entering.
Ask someone else to remove old compost, mouldy pots and decaying plants.
Use wet-wiping rather than dry sweeping where appropriate.
Do not use a leaf blower inside.
Do not store open compost beside a frequently used chair or workspace.
If the building smells strongly musty or has extensive visible mould, avoid entering until it has been dealt with.

What About Pollen and Asthma?

Fungal exposure is not the only gardening issue. Grass and other plant pollen can aggravate allergic rhinitis and asthma in susceptible people.

If pollen is one of your triggers:

check the pollen forecast
avoid mowing or being nearby while grass is cut
garden outside peak pollen periods where possible
choose plants less likely to release large quantities of wind-borne pollen
change clothes and wash after high-pollen exposure
keep asthma and allergy treatment under review

Pollen sensitivity and Aspergillus sensitivity are not the same thing, although a person may have both.

When Should I Seek Medical Advice?

A brief garden exposure does not automatically mean that you have developed a new fungal infection, and it is not usually possible to attribute ordinary day-to-day symptoms to a single exposure.

Follow your existing respiratory action plan and seek advice if symptoms are new, persistent or substantially worse than usual, particularly:

increasing cough, wheeze or chest tightness that does not settle
worsening breathlessness
fever or feeling systemically unwell
new or increased coughing of blood
a sustained fall in oxygen levels from your usual range

Seek urgent medical help for severe breathing difficulty, blue or grey lips or skin, confusion, chest pain, fainting or significant haemoptysis. Follow the emergency advice appropriate to your country.

If you are severely immunocompromised and have had a major soil, compost or mould exposure, contact your specialist team for individual advice rather than starting or changing antifungal treatment yourself.

Finding a Sustainable Balance

Gardening offers genuine physical and emotional benefits. The aim of this guidance is not to remove those benefits unnecessarily.

For many people with aspergillosis, a workable balance is to continue lower-exposure activities while delegating compost handling, leaf blowing, shredding, dry sweeping and other jobs that generate concentrated dust. Correctly fitted respiratory protection adds another layer when exposure cannot be avoided.

People at high risk of invasive aspergillosis need more cautious, personalised advice and may need to avoid soil and compost work during vulnerable periods.

Keep the garden where possible; change the way the riskiest jobs are done.

GAtherton

Quick answer

Contents

Where Does Indoor Moisture Come From?

Find the Cause Before Buying a Dehumidifier

What Humidity Should I Aim For?

When Is a Dehumidifier Helpful?

Compressor, Desiccant or Mini Dehumidifier?

How to Choose a Suitable Model

Do not rely on the advertised litres per day alone

Useful features

How to Use a Dehumidifier Effectively

Cleaning and Preventing Fungal Growth

How to Calculate the Running Cost

What Does This Mean for Someone With Aspergillosis?

If You Rent Your Home

Summary

Further Reading and References

Quick guide

Contents

Why Can Gardening Create an Exposure?

Does Everyone With Aspergillosis Need the Same Precautions?

Which Gardening Jobs Create the Most Exposure?

Lower-Exposure Ways to Enjoy Gardening

Compost, Potting Mix, Mulch and Bark

If possible, ask someone else to:

Choosing and Using a Mask

Before, During and After Gardening

Before

During

After

Greenhouses, Sheds and Enclosed Spaces

What About Pollen and Asthma?

When Should I Seek Medical Advice?

Finding a Sustainable Balance

Further Reading and References

GAtherton

What is amphotericin B?

What did the original study find?

How is this different from azole resistance?

New research is explaining how resistance works

Why does species identification matter?

Could newer medicines preserve the benefits of amphotericin B?

What does this mean for patients?

Protecting an important treatment for the future

References

What is NTM lung disease?

How does NTM affect the lungs?

Why can NTM and aspergillosis occur together?

What forms of aspergillosis may occur?

Why can the diagnosis be difficult?

What does recent research show?

How is NTM lung disease diagnosed?

How is CPA investigated?

Can treatment for one condition affect the other?

What does this mean for someone with NTM?

Reducing exposure to NTM

Related information

Further reading

Paper of the week: treating an abscess inside a CPA cavity

Dense mucus on CT may help identify ABPA

Genetic variants did not predict viral-associated aspergillosis

Early signs of resistance to olorofim

Why voriconazole blood tests remain important

What does this mean for patients?

The key difference

What is COPD?

What is bronchiectasis?

Why are widened airways a problem?

How are the conditions diagnosed?

Diagnosing COPD

Diagnosing bronchiectasis

Can someone have both COPD and bronchiectasis?

Where does aspergillosis fit?

What about asthma and other lung diseases?

Why might doctors change the diagnosis?

Can poor treatment response suggest another diagnosis?

Why identifying the full picture matters

Related information

Further reading

What is bronchiectasis?

Why can bronchiectasis increase the risk of aspergillosis?

Different Aspergillus-related conditions

Aspergillus sensitisation

Allergic bronchopulmonary aspergillosis

Aspergillus bronchitis

Chronic pulmonary aspergillosis

What does recent research show?

Can ABPA cause bronchiectasis?

Symptoms can overlap

How might doctors investigate Aspergillus-related disease?

Why CT scans are important

When should someone with bronchiectasis seek further assessment?

How is treatment decided?

Related information

Further reading

What is COPD?

What is aspergillosis?

Why can COPD increase the risk of aspergillosis?

New research: Aspergillus allergy and sensitisation in COPD

Chronic pulmonary aspergillosis and COPD

Could Aspergillus be contributing to repeated COPD flare-ups?

Why steroids need careful balancing

How might doctors investigate aspergillosis?

When should someone with COPD seek further assessment?

Related information

Further reading

What is sarcoidosis?

Why can sarcoidosis increase the risk of aspergillosis?

How common is the association?

Symptoms can overlap

Why scans may need careful interpretation

The challenge of steroid treatment

What does recent research show?

How might doctors investigate aspergillosis?

Why specialist review may be helpful