Hypersensitivity pneumonitis

Alternative names:

allergic alveolitis; detergent worker's lung; farmer's lung; humidifier lung; mushroom picker's disease

Definition:

An inflammation in the lungs caused by exposure to an allergen (foreign substance), usually an organic dust.

Causes, incidence, and risk factors:

This is usually an occupational disease in which exposure to organic dusts, fungus, or molds leads to acute and eventually chronic lung disease. Fungus may also be present in humidifiers, heating systems, and air conditioners. Acute illness may occur 4 to 8 hours after exposure, after the worker goes home, or at night. Chronic illness with changes seen on chest X-ray can develop. Occupational lung diseases can lead to diffuse interstitial pulmonary fibrosis. The incidence is 1 out of 10,000 people.