Hypersensitivity Pneumonitus is a disease of the lungs involving inflammation from triggers in the environment. Specifically, certain types of inhaled dust, often that the individual is allergic to, can cause hypersensitivity pneumonitis.
The first time the dust is inhaled, it usually does not lead to a reaction. But after many exposures to the dust, some people will react with symptoms. The little air sacs in the lungs are inflamed, with the swelling caused by white blood cells. The air sacs may also fill with fluid.
Both of these conditions cause the person to experience significant difficulty oxygenating the body with breathing. Unfortunately, over time, the regular inflammation caused by chronic exposure can create scar tissue in the lungs, for which there is no cure.
In the early stages of this disease, if the individual changes the environment so as to no longer be exposed to the offending dust, then the symptoms can be completely reversed. But if the patient ignores the warning signs and does not end exposure to the dust, he or she may develop pulmonary fibrosis, which is the scarring of the lungs. Eventually this can become bad enough that the person can't breathe on their own and requires an oxygen concentrator.
Causes of hypersensitivity pneumonitis include inhaled dust from fungus, barley, cork, moldy sugar cane, maple bark, coffee beans, paprika, mushroom compost, bird droppings and feathers, and animal hair and dander.