Aspergillus Symptoms: Infection, Allergy and Mould at Home

Aspergillus is one of the most common moulds in the world. It grows outdoors and in water-damaged buildings. Everyone breathes in its spores every day. Spores are the tiny seeds that moulds spread through the air. In healthy people, the immune system usually clears them without any symptoms [1].

Aspergillus causes illness mainly in three situations:

• in people who are allergic to it: allergic asthma, ABPA and hypersensitivity pneumonitis
• in people whose lungs are already damaged: aspergilloma and chronic pulmonary aspergillosis
• in people with a seriously weakened immune system: invasive aspergillosis

These are recognised diseases with established tests. CIRS (Chronic Inflammatory Response Syndrome) is a different and more debated condition. In CIRS, the body reacts with chronic inflammation to the whole mixture of microbes and toxins in a water-damaged building.

This article explains which Aspergillus species grow indoors and what symptoms each Aspergillus disease causes. It also explains how they differ from CIRS and what to do if you suspect a problem.

What is Aspergillus and where does it grow?

Aspergillus is a genus, a family of closely related moulds, with hundreds of species. Its natural home is soil and decaying plants, but it grows readily on damp building materials.

Aspergillus fumigatus is the species behind most Aspergillus infections. Its spores are very small, so they reach deep into the lungs. It also grows well at body temperature [1].

Which Aspergillus species grow in water-damaged buildings?

A Danish study looked at more than 5,300 samples from damp or water-damaged building materials. Aspergillus versicolor was, together with Penicillium chrysogenum, the most common mould species. A. fumigatus, A. niger, A. ochraceus and A. melleus were linked especially with concrete and other floor materials [2].

Do indoor Aspergillus moulds make toxins?

Mycotoxins are toxins made by moulds. Indoor Aspergillus species usually make fairly small amounts of them. There is one exception: A. versicolor can make large amounts of sterigmatocystin on very wet materials [3].

Other Aspergillus species make toxins such as ochratoxin A, aflatoxins and gliotoxin. Most aflatoxin exposure, however, comes from food [4].

Visible mould, a musty smell and old leaks are the usual signs of water damage. You cannot tell which mould species is growing just by looking at it.

What are the symptoms of Aspergillus exposure?

The symptoms depend on which disease Aspergillus causes. That depends more on your lungs and immune system than on the amount of mould.

Disease	Who gets it	Typical warning sign
Allergy and asthma	People sensitised to mould	Blocked nose, wheezing, asthma that is hard to control
ABPA	People with asthma or cystic fibrosis	Worsening asthma, brownish mucus plugs
Hypersensitivity pneumonitis	People repeatedly breathing in mould spores	Breathlessness, dry cough, fever a few hours after exposure
Aspergilloma and CPA	People with damaged lungs	Long-lasting cough, coughing up blood
Invasive aspergillosis	People with a seriously weakened immune system	Fever that does not respond to antibiotics

The details for each disease follow below.

Allergy and asthma

Well studied Moulds, including Aspergillus, are common allergens: substances that trigger allergies. Damp and mouldy buildings are consistently linked with asthma, wheezing, coughing, shortness of breath, respiratory infections, allergic rhinitis (hay-fever-like nose symptoms) and eczema [5].

Being sensitised means your immune system has learned to react to something. Sensitisation to fungi such as Aspergillus is closely linked with more severe asthma [6].

Typical symptoms: a blocked or runny nose, sneezing, itchy eyes, coughing, wheezing and asthma that is hard to control.

Allergic bronchopulmonary aspergillosis (ABPA)

ABPA is an excessive allergic reaction to Aspergillus growing in the airways. It occurs mainly in people with asthma or cystic fibrosis, an inherited disease that makes mucus thick and sticky.

To diagnose it, a doctor needs proof of sensitisation to Aspergillus and a markedly raised total IgE. IgE is the type of antibody involved in allergies. Further findings are also needed, such as Aspergillus-specific IgG antibodies, high eosinophil counts or typical changes on imaging [7]. Eosinophils are white blood cells that increase in allergies.

Typical symptoms: worsening asthma, a persistent cough, sometimes with brownish mucus plugs, wheezing and recurrent “chest infections”. Untreated ABPA can permanently widen and damage the airways. This is called bronchiectasis.

Hypersensitivity pneumonitis

Hypersensitivity pneumonitis is inflammation of the lung tissue caused by the immune system. It happens when you breathe in an antigen, such as mould spores, again and again. An antigen is anything the immune system reacts to. Farmer’s lung is a well-known example.

The illness can be acute, meaning it comes on suddenly. Or it can develop slowly into fibrosis, which is scarring of the lungs [8].

Well studied The US Institute of Medicine found sufficient evidence of a link between mould exposure in damp buildings and hypersensitivity pneumonitis in susceptible people [9].

Typical symptoms: in the acute form, shortness of breath, a dry cough, fever, chills and aching a few hours after exposure. In the chronic form, gradually worsening breathlessness, fatigue and weight loss.

Aspergilloma and chronic pulmonary aspergillosis

Some people’s lungs already have cavities (hollow spaces) or other damage. Examples are after tuberculosis, or with COPD or sarcoidosis. In these people, Aspergillus can slowly grow into the damaged area.

• A single fungal ball is called an aspergilloma.
• A wider, slowly worsening infection is chronic pulmonary aspergillosis (CPA).

CPA affects an estimated 240,000 people in Europe. It occurs in people who are not immunocompromised (their immune system works normally) but who have previous or current lung disease [10].

Typical symptoms: a long-lasting cough, coughing up blood, fatigue, weight loss and breathlessness. An aspergilloma can also cause no symptoms and be found by chance on a scan.

Invasive aspergillosis

Invasive aspergillosis is a serious infection. The mould invades lung tissue and can spread to other organs. It occurs mainly in people with a seriously weakened immune system. Examples are during chemotherapy for leukaemia, after a stem cell or organ transplant, or during long-term high-dose corticosteroid treatment [11]. It is rare in people with a normal immune system.

Typical symptoms: fever that does not respond to antibiotics, cough, chest pain, coughing up blood and shortness of breath.

Can Aspergillus cause fatigue and brain fog?

Fatigue is common in chronic lung disease and infections, including CPA [10].

However, Aspergillus diseases have not been shown to cause the wider set of symptoms that many people describe after falling ill in water-damaged buildings. These include brain fog (thinking that feels slow and cloudy), light sensitivity, numbness and symptoms in many organ systems.

Multi-system symptoms like these, in people living or working in water-damaged buildings, are what Dr Ritchie Shoemaker’s research describes as CIRS [12].

How is Aspergillus illness different from CIRS?

Expert opinion In Dr Shoemaker’s model, CIRS is neither an infection nor an allergy to a single mould. It is a chronic inflammatory response of the innate immune system, the body’s fast first line of defence. The response is to the whole mixture of things in the indoor air of a water-damaged building [12]:

• mould spores and fragments
• mycotoxins
• bacteria such as actinomycetes, which grow in threads like mould
• endotoxins, parts of the cell walls of certain bacteria
• other compounds

Read more in How mould causes CIRS.

	Aspergillus diseases	CIRS
Cause	Aspergillus itself: infection or allergy	Inflammatory response to the whole mixture of microbes and toxins in a water-damaged building
Who gets it	People with asthma or cystic fibrosis (ABPA), damaged lungs (CPA) or weak immunity (invasive)	According to Dr Shoemaker, mostly people with certain HLA-DR gene types
Main symptoms	Mostly in the lungs and airways	Many organ systems: fatigue, brain fog, pain, sinus symptoms, light sensitivity
Tests	Aspergillus IgE and IgG, total IgE, eosinophils, chest CT, sputum culture, galactomannan	VCS test, HLA-DR, C4a, TGF-β1, MMP-9, MSH and other markers
Treatment	Depending on the disease: antifungal medicines, corticosteroids, surgery	Ending the exposure first, then the Shoemaker protocol
Recognition	International guidelines	Described mainly by one research group; not widely recognised

HLA-DR genes are part of the body’s system for recognising what belongs in the body and what does not.

Can you have both?

Yes. The two do not rule each other out. The same water-damaged building can trigger asthma in one person and multi-system symptoms in another.

But a positive Aspergillus test does not show that you have CIRS. And CIRS does not mean that you have an Aspergillus infection.

Antifungal medicines are essential for invasive aspergillosis. Some clinicians also use them for illness from water-damaged buildings without a proven fungal infection [13]. That use is debated, and the evidence for it is limited.

How do you test for Aspergillus?

Tests in the body

The right test depends on which disease is suspected. A doctor orders the tests:

• Allergy and ABPA: Aspergillus-specific IgE (or a skin prick test), total IgE, Aspergillus IgG and blood eosinophils. International guidelines recommend that specialists check people newly diagnosed with asthma for A. fumigatus sensitisation [7].
• Hypersensitivity pneumonitis: a detailed exposure history, IgG antibodies against suspected antigens, a chest CT, and often bronchoscopy, an examination of the airways with a thin camera tube [8].
• Aspergilloma and CPA: a chest CT and Aspergillus IgG antibodies. These antibodies are raised in over 90% of patients, so in more than 9 out of 10 [10].
• Invasive aspergillosis: a CT scan and tests such as galactomannan, a part of the mould that can be measured in blood or fluid from the airways. These tests are usually done in hospital [11].

Tests in the building

Mould samples can show which species are growing. The HERTSMI-2 test, used in the CIRS world, includes two Aspergillus species, A. versicolor and A. penicillioides.

Keep in mind what a large review found. Current evidence does not support measuring specific microbes to guide health decisions. Visible dampness and mould themselves are the clearer warning sign [5].

Urine mycotoxin tests are sold commercially, but how to interpret them is debated. See ochratoxin A.

What should you do if you suspect Aspergillus exposure?

How strong is the evidence?

Well studied Aspergillus diseases are well established. These are ABPA, aspergilloma, chronic and invasive aspergillosis, and hypersensitivity pneumonitis. They have international guidelines for diagnosis and treatment [7, 8, 10, 11]. The link between damp, mouldy buildings and asthma and other respiratory symptoms is also consistent across many studies [5, 9].

Preliminary research The CIRS model, by contrast, comes mainly from Dr Shoemaker’s research group. Independent researchers have not widely confirmed it.

Both views agree on the practical conclusion. Fix water damage and reduce exposure to mouldy indoor air.

Remember these

Check yourself: Which three groups of people does Aspergillus make ill? And why does a positive Aspergillus test not show that you have CIRS?

What next?

• Read about mould exposure symptoms.
• Learn how mould causes CIRS.
• Read the water damage guide on fixing the moisture safely.

References

1. Latgé JP, Chamilos G. Aspergillus fumigatus and aspergillosis in 2019. Clin Microbiol Rev. 2019;33(1):e00140-18. PubMed
2. Andersen B, Frisvad JC, Søndergaard I, Rasmussen IS, Larsen LS. Associations between fungal species and water-damaged building materials. Appl Environ Microbiol. 2011;77(12):4180–4188. PubMed
3. Nielsen KF. Mycotoxin production by indoor molds. Fungal Genet Biol. 2003;39(2):103–117. PubMed
4. Bennett JW, Klich M. Mycotoxins. Clin Microbiol Rev. 2003;16(3):497–516. PubMed
5. Mendell MJ, Mirer AG, Cheung K, Tong M, Douwes J. Respiratory and allergic health effects of dampness, mold, and dampness-related agents: a review of the epidemiologic evidence. Environ Health Perspect. 2011;119(6):748–756. PubMed
6. Denning DW, O’Driscoll BR, Hogaboam CM, Bowyer P, Niven RM. The link between fungi and severe asthma: a summary of the evidence. Eur Respir J. 2006;27(3):615–626. PubMed
7. Agarwal R, Sehgal IS, Muthu V, et al. Revised ISHAM-ABPA working group clinical practice guidelines for diagnosing, classifying and treating allergic bronchopulmonary aspergillosis/mycoses. Eur Respir J. 2024;63(4):2400061. PubMed
8. Raghu G, Remy-Jardin M, Ryerson CJ, et al. Diagnosis of hypersensitivity pneumonitis in adults: an official ATS/JRS/ALAT clinical practice guideline. Am J Respir Crit Care Med. 2020;202(3):e36–e69. PubMed
9. Institute of Medicine. Damp Indoor Spaces and Health. Washington, DC: National Academies Press; 2004. doi:10.17226/11011
10. Denning DW, Cadranel J, Beigelman-Aubry C, et al. Chronic pulmonary aspergillosis: rationale and clinical guidelines for diagnosis and management. Eur Respir J. 2016;47(1):45–68. PubMed
11. Patterson TF, Thompson GR 3rd, Denning DW, et al. Practice guidelines for the diagnosis and management of aspergillosis: 2016 update by the Infectious Diseases Society of America. Clin Infect Dis. 2016;63(4):e1–e60. PubMed
12. Shoemaker RC, House DE. Sick building syndrome (SBS) and exposure to water-damaged buildings: time series study, clinical trial and mechanisms. Neurotoxicol Teratol. 2006;28(5):573–588. PubMed
13. Hope J. A review of the mechanism of injury and treatment approaches for illness resulting from exposure to water-damaged buildings, mold, and mycotoxins. ScientificWorldJournal. 2013;2013:767482. PubMed