Aspergillosis: when a common mold becomes an allergy, a ball, or an invasion, and the antifungal plan
Last updated September 3, 2026.
Aspergillosis is the group of conditions caused by Aspergillus, a mold that is everywhere: in soil, dust, compost, and the air everyone breathes daily without harm. It becomes a problem in three distinct ways. In allergic bronchopulmonary aspergillosis (ABPA), people with asthma or cystic fibrosis develop an allergy to the mold, and their airways inflame and plug with mucus. In chronic pulmonary aspergillosis, often in lungs already scarred by old infections, the mold slowly colonizes a cavity, sometimes forming a fungus ball. And in invasive aspergillosis, in people with severely weakened immune systems, the mold invades tissue and blood, and that form is an emergency. Diagnosis combines scans, blood tests for allergy markers and antibodies, and phlegm samples. Treatment depends entirely on which form: ABPA is treated with steroids and antifungals such as itraconazole, chronic forms with months of antifungals and sometimes surgery for a bleeding fungus ball, and invasive disease with urgent intravenous antifungals in hospital. The allergy form is the commonest, and it is under-recognized: asthma that is hard to control deserves the question.
What does it look like?
ABPA looks like asthma that will not behave: wheeze and cough despite inhalers, brownish mucus plugs, and flares that need steroid courses. Chronic pulmonary aspergillosis creeps: months of cough, weight loss, fatigue, and sometimes coughing blood, usually in someone whose lungs carry old scars. Invasive aspergillosis strikes people on chemotherapy, transplants, or high-dose steroids: fever and breathlessness that do not answer antibiotics, and it moves fast.
Why does it happen?
Aspergillus is unavoidable: its spores are in every breath of ordinary air. The difference is the host. Airways already inflamed by asthma can become allergic to it. Lungs already scarred by tuberculosis, COPD, or sarcoidosis offer it cavities to colonize. Immune systems flattened by chemotherapy or transplant drugs cannot hold the line at all. It is not contagious, you cannot catch it from another person, and nothing you did caused it; the mold is universal and the vulnerability is the variable.
How is it treated?
- ABPA: calm the allergy and reduce the mold. Steroid courses settle the inflammation, and antifungals, usually itraconazole for months, shrink the mold burden. Blood markers, especially the allergy antibody IgE, track the response and warn of flares.
- Chronic forms: months of antifungals. Itraconazole or voriconazole for long courses, with liver blood tests and interactions checked. Surgery removes a fungus ball when it bleeds or when drugs fail, and it is a real operation, chosen carefully.
- Invasive disease: an emergency treated in hospital. Intravenous voriconazole or similar, started fast, in people whose immune systems are down. The warning signs during chemotherapy or transplant, fever not answering antibiotics, are acted on immediately.
- The background condition gets managed too. Asthma control, bronchiectasis clearance, and the immune-weakening drugs all get reviewed, because aspergillosis rides on its host conditions.
When does it need the prompt review?
Coughing more than a teaspoon of blood deserves same-day assessment, and heavy bleeding is a 911 call. During chemotherapy, transplant, or high-dose steroids, a fever is a same-hour emergency. For ABPA, a worsening wheeze despite your inhalers deserves a review within days, because flares scar airways. Pymander's escalation routing is built and tested specifically for this class of decision; see the safety architecture working paper.
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Common questions
The mold is everywhere? Then is my house making me sick?
No, and this is the reassurance that matters most: Aspergillus spores are in every breath of ordinary air, in every house, on every continent, and they have been your whole life. You did not get a bigger dose than your neighbors; your immune system developed an allergy to a universal substance. The problem is the response, not the address, so no remediation, moving, or bleaching will fix it, and anyone selling you that is selling fear. The exceptions worth knowing are heavy exposures, compost heaps, moldy buildings, and marijuana, which are worth avoiding, but ordinary home life is not the enemy.
Why did it take two years to find?
Because ABPA wears asthma's clothes. Its symptoms, wheeze, cough, breathlessness, are asthma's symptoms, and the standard response to worsening asthma is more asthma treatment, which partially works and resets the clock. The tells, brown mucus plugs, repeated steroid courses, blood and phlegm tests that finally pointed, tend to be assembled only when someone hunts for the condition, as your new lung doctor did. Two years is frustratingly typical, not negligent. The good news is that the diagnosis now unifies the whole story and the treatment is aimed at the actual mechanism, not just the symptoms.
What does itraconazole actually do, and what do I need to know about taking it?
Itraconazole shrinks the mold burden in your airways, which reduces the fuel for the allergic inflammation, and courses typically run for months. The things to know: it interacts with a long list of medicines, including some inhalers and many common prescriptions, so every new medicine, including over-the-counter ones, gets checked against it. It can affect the liver, so blood tests are part of the deal. It absorbs best with food and an acidic stomach, and the team will tell you the specifics for your formulation. Side effects like nausea and ankle swelling are worth reporting, not enduring, because alternatives exist.
How will we know it is working?
Three ways, and they line up. Your symptoms should ease over weeks to months: less wheeze, fewer plugs, fewer steroid rescues. Your blood tests track the allergy antibody IgE, which falls when the condition is controlled and rises to warn of a flare, which is why the blood appointments matter even when you feel fine. And your breathing tests, done at intervals, show whether your airways are being protected. The goal is control rather than cure: fewer flares, fewer steroid courses, and airways protected from the slow scarring that untreated ABPA causes.
Is this going to keep getting worse?
The honest answer is that ABPA is a long-term companion, and treated well it usually stabilizes: the flares get rarer and milder, the steroid burden drops, and life returns to something like the asthma you knew. Untreated, it slowly scars airways, which is the reason the treatment is worth its months. Some people need repeated courses over the years, and some qualify for the newer injection treatments for severe allergic asthma, which have changed the outlook for the hard-to-control cases. The trajectory is set much more by the treatment plan than by the mold, and yours has started.
Can I pass this to my family? And should they avoid me when I am coughing?
No on both counts. Aspergillosis is not contagious: you cannot pass the mold allergy to anyone, because the mold is already everywhere and the allergy is yours alone. Your family breathes the same spores today that they always have, and their lungs treat them as the background noise they are. Nobody needs to avoid you, your cough, or your kitchen. The only household conversation worth having is the compost-heap one: heavy mold exposures, compost turning, moldy buildings, and marijuana smoke are worth you personally avoiding, because your airways have declared their sensitivity.