What is hypersensitivity pneumonitis?

The term hypersensitivity pneumonitis (also known as extrinsic allergic alveolitis) refers to a group of lung diseases in which your lungs become inflamed as an allergic reaction resulting from exposure to dusts of animal and vegetable origin. The name “extrinsic allergic alveolitis”, although complicated, describes the origin and the nature of these diseases.

• "extrinsic"-- cause originating outside the body
• "allergic"-- caused by the allergic reaction of the body to a specific substance or condition
• "alveolitis"-- an inflammation in the inner part of the lungs (alveoli are the small air sacs in the lungs)

What causes hypersensitivity pneumonitis?

Intense or […]