SAFS: Severe Asthma with Fungal Sensitisation

Woman using an inhaler with a spacer at home to manage severe asthma. — Optimising asthma treatment is the foundation of care for severe asthma with fungal sensitisation.

Severe asthma with fungal sensitisation (SAFS) is a form of difficult-to-control asthma in which the immune system reacts to fungi in the environment, including Aspergillus.

People with SAFS have severe asthma and evidence of fungal allergy, but do not have the fuller pattern of allergic lung disease seen in allergic bronchopulmonary aspergillosis (ABPA).

Developed with patients

This information has been developed with patients and carers alongside clinical specialists. It is evidence based and regularly reviewed, and is intended to support—not replace—advice from your own healthcare team.

Key points

SAFS means severe asthma alongside sensitivity or allergy to one or more fungi.
It is different from ABPA, although the conditions can overlap and share some features.
Symptoms are those of severe, poorly controlled asthma: wheeze, cough, breathlessness, chest tightness and frequent flare-ups.
There is no single test for SAFS. Diagnosis involves confirming fungal sensitisation and carefully excluding ABPA and other causes.
Treatment focuses first on the best possible severe-asthma care.
Antifungal medicines may help selected people, but are not suitable or necessary for everyone.

What is SAFS?

Fungal spores are a normal part of the air around us, indoors and outdoors. Most people breathe them in without becoming ill. In some people with asthma, however, the immune system recognises proteins from fungi as allergens. This can add to airway inflammation and make asthma harder to control.

SAFS is usually considered when someone has severe asthma, evidence of fungal sensitisation and no clear evidence of ABPA. Fungi linked with airway allergy can include Aspergillus, Alternaria, Cladosporium and Penicillium.

SAFS is an area of active research. It is useful as a clinical description, but it does not mean that every person with fungal allergy has a fungal infection or needs antifungal treatment.

How is SAFS different from ABPA?

Both SAFS and ABPA involve an immune reaction to fungi, often Aspergillus. The difference is in the overall pattern of illness and test results.

SAFS involves severe asthma and fungal sensitisation, without the full diagnostic features of ABPA.
ABPA is a more specific allergic lung condition. It can involve very high total IgE, mucus plugging, characteristic scan changes and bronchiectasis.

These conditions are sometimes described as being on a spectrum. That does not mean that everyone with SAFS will develop ABPA. Many people remain stable with SAFS, particularly when their asthma is well managed.

Who may be affected?

SAFS is considered in people whose asthma remains difficult to control despite appropriate treatment. It may be more likely when a person has:

Frequent asthma flare-ups or courses of oral steroids
Ongoing symptoms despite high-dose inhaled treatment
Evidence of fungal allergy on a skin-prick or blood test
A history suggesting that symptoms worsen at particular times of year or in certain environments

Environmental damp or obvious mould may worsen symptoms for some people, but it is often impossible to prove exactly how much fungal exposure contributes in one individual. Trying to avoid all fungi is neither realistic nor necessary.

Symptoms

The symptoms of SAFS are usually those of severe, difficult-to-control asthma. They can include:

Wheeze
Breathlessness
Chest tightness
Persistent cough
Night-time asthma symptoms
Frequent flare-ups or the need for rescue steroid courses
Asthma that responds less well than expected to usual treatment

These symptoms are not specific to SAFS. Asthma can be worsened by infections, inhaler technique, smoking, reflux, rhinitis, anxiety, dysfunctional breathing and many other factors. A thorough severe-asthma assessment is important.

How is SAFS diagnosed?

There is no single test that proves SAFS. Diagnosis is based on the whole clinical picture and is usually made by a respiratory or severe-asthma specialist.

Assessment may include:

A review of asthma symptoms, flare-ups and current treatment
Checking inhaler technique and whether treatment is being taken regularly
Skin-prick testing or blood tests for fungus-specific IgE
Total IgE and eosinophil blood tests
Lung-function testing
A chest X-ray or CT scan if needed to look for mucus plugging, bronchiectasis or another diagnosis
Assessment for ABPA and other Aspergillus-related conditions

Treatment

Treatment is individual and begins with the best possible management of severe asthma. The aim is to reduce symptoms and flare-ups, improve day-to-day life and minimise the need for oral steroids where possible.

Optimising asthma care

This may include reviewing inhaler technique, regular use of prescribed inhalers, trigger management and treatment of related problems such as allergic rhinitis, reflux or dysfunctional breathing.

Airway clearance may be useful for people who also have troublesome mucus or bronchiectasis, but it is not needed by everyone with SAFS.

Biologic medicines

Biologic medicines are now an important option for many people with severe asthma. The most suitable treatment depends on the individual asthma pattern, including allergy, eosinophil count, flare-up history and other health conditions.

Examples include omalizumab, mepolizumab, benralizumab, dupilumab and tezepelumab. A severe-asthma specialist can discuss whether a biologic is appropriate and what benefit to expect.

Oral steroids

Short courses of oral steroids may be needed for severe flare-ups. Long-term oral steroid treatment is generally avoided where possible because it can cause significant side effects. If regular steroid courses are needed, it is worth asking for a specialist review of the overall asthma plan.

Antifungal medicines

Antifungal medicines, such as itraconazole, may help some carefully selected people with SAFS. However, the benefit is variable and the evidence is less certain than for standard severe-asthma treatments.

Antifungals can interact with many other medicines and may need liver-function tests and drug-level monitoring. They should only be started after a specialist discussion of the likely benefits, risks and alternatives.

What can I do about mould and fungal exposure?

It is sensible to reduce avoidable exposure to obvious damp and mould in the home. Repairing leaks, improving ventilation and reducing condensation can all support respiratory health.

Some people notice symptoms when gardening or around compost, mulch or decaying plant material. If this happens to you, practical measures such as avoiding direct handling, asking someone else to do the task or wearing appropriate protection may help. There is no need to become fearful of ordinary outdoor life: fungi are naturally present everywhere.

When should I seek medical advice?

Speak to your GP, asthma nurse or respiratory team if your asthma remains poorly controlled, you are having repeated flare-ups, you need frequent courses of oral steroids, or you have questions about fungal allergy, ABPA or antifungal medicines.

Seek urgent help if you are severely breathless, cannot speak in full sentences, have blue lips, feel confused or drowsy, or your reliever inhaler is not helping as expected.