When you breathe in tiny particles from mold, bird droppings, or dust from certain work environments, your lungs can react in a way that isn’t normal — this is hypersensitivity pneumonitis, an immune-mediated lung inflammation triggered by repeated exposure to environmental allergens. Also known as allergic alveolitis, it’s not an infection or cancer, but your body’s overreaction to things most people ignore. Think of it like a persistent allergic reaction deep inside your lungs, not in your nose or skin. It doesn’t show up right away — it builds over weeks, months, or even years of exposure.
People who work with birds — like pigeon breeders or poultry workers — often get it from inhaling feather dust or droppings. Farmers dealing with moldy hay, coffee bean processors, and even home aquarium owners have been diagnosed after long-term exposure. It’s not rare in these settings. What makes it tricky is that symptoms mimic a cold or flu: cough, shortness of breath, fever, fatigue. Many doctors miss it because they don’t ask about your job, hobbies, or home environment. If you’ve had recurring respiratory issues and no one can find a clear cause, hypersensitivity pneumonitis might be the missing piece.
The condition falls under a group of lung diseases called occupational lung diseases, lung conditions caused or worsened by workplace exposures. It’s closely tied to environmental triggers, specific airborne substances that set off the immune response in sensitive individuals. The key to stopping it isn’t more medication — it’s removing the trigger. Once you identify what’s causing it — whether it’s your hot tub, your parakeet, or the mold in your attic — getting away from it can reverse the damage. If you keep breathing it in, though, it can lead to permanent scarring in the lungs, a condition called pulmonary fibrosis.
Diagnosis isn’t simple. Doctors look at your history, do breathing tests, and often need a high-res CT scan of your lungs. Blood tests and sometimes even a lung biopsy help confirm it. Treatment usually starts with avoiding the trigger, then adding steroids if inflammation is severe. But steroids don’t fix the root problem — only stopping exposure does.
In the articles below, you’ll find real-world stories and practical advice from people who’ve been there. You’ll learn how to spot hidden triggers in your home, what tests actually matter, how to talk to your doctor without sounding paranoid, and what steps to take before it’s too late. This isn’t about rare diseases — it’s about common exposures that slip under the radar. If you’ve been told your cough is "just allergies" and nothing’s helped, these posts could change everything.
Hypersensitivity pneumonitis causes cough and breathlessness from inhaled environmental triggers like bird droppings or mold-not medications. Early diagnosis and avoiding the trigger can prevent permanent lung damage.