What is Aspergillosis? - Aspergillosis Patients & Carers Support

Aspergillosis is a group of illnesses caused by a common mould called Aspergillus. This mould is found naturally in the environment and releases microscopic spores into the air. We breathe in these spores every day without noticing.

Most people never become ill because their immune system clears the spores from the airways and lungs. However, in some people, especially those with asthma, other lung disease, or a weakened immune system, Aspergillus can cause allergic reactions, persistent airway problems, or infection.

This page is a starting point. It explains the basics and helps you find the most useful information elsewhere on this website.

Key Points

Aspergillosis is caused by the mould Aspergillus.
Aspergillus spores are common in the air and most people breathe them in every day.
Most people do not become ill.
Aspergillosis is not one single disease. It is a group of different conditions.
Some forms are mainly allergic conditions; others are infections.
The type of illness depends on your lungs, your immune system, and how your body reacts to the fungus.

New to Aspergillosis?

If you have recently been diagnosed, or your doctor suspects aspergillosis, these links may help you get started:

Where Does Aspergillus Come From?

Aspergillus is a mould that grows naturally in the environment. It may be found in soil, compost, decaying leaves, dust, and damp indoor areas. Because it is so common, its spores are often present in the air around us.

Most of the time this is not a problem. Healthy lungs and a healthy immune system usually remove the spores without difficulty. Problems can arise if the lungs are already damaged, the airways are sensitive, or the immune system is weakened or altered.

Figure 1. Breathing in *Aspergillus* spores does not usually cause illness, but in some people it can lead to allergic disease, chronic infection, or severe infection.

Aspergillosis Is a Group of Conditions

The word aspergillosis does not describe one single illness. It is an umbrella term for several related conditions caused by Aspergillus. The main difference between these conditions is the way the body reacts to the fungus.

Figure 2. Aspergillosis includes allergic forms, chronic infections, and more severe invasive infections.

Allergic Aspergillus Conditions

In some people, especially those with asthma or related airway disease, the immune system overreacts to Aspergillus. The fungus may not be invading tissue, but it can still trigger substantial inflammation and symptoms.

Chronic Aspergillus Infections

In other people, particularly those with pre-existing lung damage, Aspergillus can persist in the lungs and cause long-term infection or inflammation.

Severe or Invasive Infection

People with severely weakened immune systems can develop invasive aspergillosis, in which the fungus grows more aggressively and can become a medical emergency.

Invasive aspergillosis

Who Is Most at Risk?

Most people breathe in Aspergillus spores without becoming ill. Risk increases when the lungs are already vulnerable or the immune system cannot respond in the usual way.

People who may be at higher risk include:

people with asthma
people with bronchiectasis
people with chronic obstructive pulmonary disease (COPD)
people who have had tuberculosis or other lung damage
people with cystic fibrosis
people taking medicines that suppress the immune system
people whose immune systems are weakened by illness or medical treatment

What Symptoms Can Aspergillosis Cause?

Symptoms vary depending on the type of aspergillosis, but common symptoms may include:

persistent cough
breathlessness
wheezing
bringing up sputum or mucus plugs
chest discomfort
fatigue
weight loss
coughing up blood in some cases

These symptoms can overlap with many other lung conditions, which is one reason aspergillosis may take time to diagnose.

Why Can Aspergillosis Be Difficult to Diagnose?

Aspergillosis can be difficult to recognise because it is a group of conditions rather than one disease, and its symptoms often overlap with asthma, bronchiectasis, chronic lung infection, or other respiratory illnesses.

Doctors may use a combination of evidence, including symptoms, scans, blood tests, sputum results, and the patient’s medical history. One test alone is often not enough.

How Is Aspergillosis Treated?

Treatment depends on the type of aspergillosis. Some people need antifungal medicines. Others may need steroids, biologic drugs, airway clearance, monitoring, or a combination of treatments. Some conditions need long-term management rather than a short course of treatment.

Living With Aspergillosis

Living with aspergillosis often involves more than treating the fungus itself. Many people also need help with fatigue, breathlessness, exercise, nutrition, anxiety, practical adjustments, and understanding how to reduce harmful exposures.

Support from other patients, carers, and specialist teams can make a real difference.

Support and Community

Being diagnosed with a rare condition can feel isolating. Many patients and carers find it helpful to speak to others who understand the challenges of living with aspergillosis.

Our support meetings and patient resources aim to provide reliable information, shared experience, and a sense of community.

Find out about our patient support meetings →

Common Questions

Is aspergillosis contagious?

No. Aspergillosis is not usually passed from one person to another.

Does everyone who breathes in Aspergillus get ill?

No. Most people breathe in spores regularly without becoming ill.

Is aspergillosis one disease?

No. It is a group of different conditions caused by Aspergillus.

Can aspergillosis be cured?

That depends on the type. Some forms can be treated effectively, while others need long-term monitoring and management.

Why have I never heard of it before?

Some forms of aspergillosis are uncommon, and many symptoms overlap with more familiar lung conditions. This can make diagnosis and awareness more difficult.

Where to Go Next

Last reviewed: March 2026