Hypersensitivity Pneumonitis: Mistakes That Slow Recovery
Hypersensitivity pneumonitis is what happens when lungs react to something you keep breathing in: moldy hay, bird droppings, a contaminated humidifier, metalworking mist. Doctors used to call it extrinsic allergic alveolitis, and the old names still help. Bird fancier's lung. Farmer's lung. The pattern is delayed, which is exactly why it gets missed. Symptoms typically appear 4 to 8 hours after exposure, so someone who cleans a pigeon coop at noon feels fine and is coughing and feverish by dinner. This is not asthma, and it is not an allergy in the sneezing sense. It is an immune reaction inside the air sacs, and it can scar lung tissue when the trigger stays in the air. Registry series report 5-year mortality near 20 percent once fibrosis is visible on CT, which is why decisions made in the first year matter more than any supplement on this page. Here is what drives it, what it feels like, and the mistakes that keep lungs inflamed long after the source is gone.