Invasive aspergillosis (IA) is the most severe form of aspergillosis. It is a serious fungal infection that usually affects people whose immune systems are extremely weakened (i.e. far more than patients with chronic forms fof aspergillosis eg CPA, ABPA). The infection most often starts in the lungs, but it can spread to other parts of the body if not treated quickly.
This page explains what invasive aspergillosis is, who is at risk, the symptoms to look out for, how it is diagnosed, and how it is treated.
Key points
- Invasive aspergillosis (IA) is a life-threatening infection caused by Aspergillus mould.
- It mainly affects people with severely weakened immune systems.
- It usually begins in the lungs but can spread to other organs.
- Symptoms can include fever, cough, breathlessness, chest pain, and coughing up blood.
- Diagnosis usually involves scans, blood tests, and respiratory samples.
- Treatment needs to start urgently, usually in hospital, using specialist antifungal medicines.
Table of contents
- Overview
- Who is at risk?
- Symptoms
- Causes
- Diagnosis
- Treatment
- Possible complications
- Common questions patients ask
- When to seek urgent medical care
- References
Overview
Invasive aspergillosis is a serious infection caused by fungi from the Aspergillus family, most commonly Aspergillus fumigatus. Unlike allergic forms of aspergillosis, invasive aspergillosis happens when the fungus grows into body tissues rather than simply triggering inflammation or allergy.
In most cases, the infection starts after a person breathes in tiny fungal spores from the environment. Healthy immune systems usually destroy these spores quickly. But in people with severe immune suppression, the spores can germinate, grow into fungal threads called hyphae, and invade lung tissue and blood vessels.
The lungs are usually affected first, but invasive aspergillosis can sometimes spread to other organs such as the brain, skin, kidneys, or heart. Because of this, it is considered a medical emergency and needs urgent specialist treatment.
For most patient information, the correct name is simply invasive aspergillosis. It is usually an acute, rapidly progressive infection, so adding the word “acute” is not usually necessary.
Who is at risk?
Invasive aspergillosis mainly affects people who are severely immunocompromised, meaning their immune defences are not working well enough to control infection.
People at higher risk include those with:
- Leukaemia or lymphoma, especially during intensive chemotherapy
- Neutropenia (very low levels of infection-fighting white blood cells called neutrophils)
- Stem cell or bone marrow transplants
- Solid organ transplants, especially lung transplants
- High-dose corticosteroid treatment or other strong immunosuppressive medicines
- Advanced immune deficiency from severe illness
- Intensive care admission, particularly after severe influenza or severe viral pneumonia
Some people with severe lung disease such as chronic obstructive pulmonary disease (COPD) may also be at risk, especially if they are very unwell or receiving steroid treatment.
Symptoms
The symptoms of invasive aspergillosis can vary depending on which organs are involved, but lung symptoms are the most common.
Common symptoms include:
- Fever, especially fever that does not improve with antibiotics
- Cough
- Shortness of breath
- Chest pain, especially pain that worsens with breathing
- Coughing up blood (haemoptysis)
- Fatigue and weakness
If the infection spreads beyond the lungs, symptoms may also include:
- Headaches
- Confusion or other neurological symptoms
- Skin lesions
- Joint pain
- Visual problems
These symptoms are not unique to invasive aspergillosis, which is one reason diagnosis can be difficult. In people at high risk, persistent fever, breathlessness, chest pain, or haemoptysis should always be taken seriously.
Causes
Aspergillus spores are extremely common in the environment. They are found in:
- Soil
- Compost
- Decaying leaves and plant material
- Dust
- Damp or mouldy environments
Most people breathe in these spores every day without becoming ill. Problems arise when the body cannot clear them properly.
In invasive aspergillosis, the spores settle in the lungs and begin to grow. Instead of being removed by immune cells, the fungus invades lung tissue and may enter blood vessels. This can damage the lungs, cause bleeding, and allow the infection to spread elsewhere in the body.
So the main cause is not simply exposure to the mould itself, but exposure in the setting of a severely weakened immune system.
Diagnosis
Diagnosing invasive aspergillosis can be difficult because the symptoms are often non-specific and may look similar to bacterial infection, other fungal infections, or complications of the underlying illness.
Diagnosis usually relies on a combination of clinical judgement, scans, laboratory tests, and microbiology.
Imaging
A CT scan of the chest is often one of the most important tests. It may show nodules, areas of inflammation, or other changes suggestive of fungal infection.
Blood tests
Specialist blood tests may include:
- Galactomannan
- Beta-D-glucan
These tests can support the diagnosis, especially in the right clinical setting, but they are not perfect on their own.
Respiratory samples
Doctors may test:
- Sputum
- Bronchoscopy samples such as bronchoalveolar lavage (BAL)
These samples can be examined by:
- Culture
- Microscopy
- Polymerase chain reaction (PCR) testing
- Galactomannan testing
Tissue biopsy
Sometimes a biopsy is needed to confirm that the fungus is truly invading tissue rather than simply being present in the airways. This is not always possible in very unwell patients, but when it can be done, it may provide the clearest evidence.
Because no single test gives all the answers, diagnosis often depends on putting several pieces of information together.
Treatment
Invasive aspergillosis requires urgent treatment, usually in hospital. Delays can be dangerous.
Antifungal treatment
The main treatment is with specialist antifungal medicines. Commonly used drugs include:
- Voriconazole
- Isavuconazole
- Liposomal amphotericin B
Treatment may start with an intravenous (IV) antifungal and then continue with tablets or capsules later, depending on the patient’s condition and the drug used.
Managing the underlying cause
Successful treatment also depends on improving the body’s ability to fight infection where possible. This may include:
- Reducing immunosuppressive medicines if it is safe to do so
- Supporting recovery from neutropenia
- Treating the underlying illness
Monitoring
Patients usually need close monitoring, including blood tests, scans, and review of drug side effects and interactions. Some antifungal medicines interact with many other drugs, so specialist oversight is important.
Surgery
Occasionally, surgery may be needed, for example if there is severe bleeding or a localised area of infection that needs to be removed.
Treatment often continues for weeks or months, depending on how quickly the immune system recovers and how well the infection responds.
Possible complications
Invasive aspergillosis can lead to very serious complications, especially if diagnosis or treatment is delayed. These may include:
- Severe lung damage
- Respiratory failure
- Major bleeding from the lungs
- Spread to the brain or other organs
- Multi-organ failure
Even with good treatment, invasive aspergillosis can still be very dangerous. Outcomes are best when the infection is recognised early and treated promptly.
Common questions patients ask
Is invasive aspergillosis contagious?
No. It is not passed from person to person. People develop it by breathing in spores from the environment when their immune system is too weak to clear them.
Can healthy people get invasive aspergillosis?
It is very uncommon in healthy people. Most cases occur in those with severe immune suppression or critical illness.
Is this the same as allergic bronchopulmonary aspergillosis or chronic pulmonary aspergillosis?
No. These are different forms of aspergillosis.
- Allergic bronchopulmonary aspergillosis (ABPA) is an allergic reaction to Aspergillus.
- Chronic pulmonary aspergillosis (CPA) is a long-term infection, usually in people with underlying lung damage.
- Invasive aspergillosis (IA) is a rapidly progressive infection in people with major immune weakness.
Is invasive aspergillosis always in the lungs?
It usually starts in the lungs, but it can spread to other parts of the body, especially in severe cases.
How long does treatment last?
There is no single answer. Treatment often continues for at least several weeks and sometimes much longer, depending on response and immune recovery.
When to seek urgent medical care
People at high risk of invasive aspergillosis should seek urgent medical help if they develop:
- Persistent or unexplained fever
- Increasing shortness of breath
- Chest pain
- Coughing up blood
- Severe headache, confusion, or new neurological symptoms
Invasive aspergillosis can progress quickly, so prompt assessment is important.
References
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Last reviewed: March 2026
Author: Aspergillosis.org editorial team
Medical review: Specialist review recommended before publication