hypersensitivity pneumonitis, an inflammatory form of interstitial pneumonia that results from an immunological reaction in a hypersensitive person. The reaction may be provoked by a variety of inhaled organic dusts, often those containing fungal spores. The disease can be prevented by avoiding contact with the causative agents. Classification of the disease is based solely on the character of the immune response rather than on its clinical manifestations. A wide variety of symptoms may occur, including asthma, fever, chills, malaise, and muscle aches, which usually develop 4 to 6 hours after exposure. Laboratory examination of the blood commonly reveals leukocytosis. Recovery is usually spontaneous. In an acute attack, corticosteroids may be given to diminish the inflammatory response. Also called extrinsic allergic alveolitis. Kinds include bagassosis, cork worker’s lung, farmer’s lung, humidifier lung, mushroom worker’s lung. See also Arthus reaction.
