Hypersensitivity pneumonitis is a pulmonary disease characterized by an immune (allergic) inflammation of interstitium and alveolar wall.
The etiology is varied (from spores to cotton fibers). The pathogenesis is a hypersensitivity (allergic) reaction to inhaled, foreign antigens.
Fever, respiratory difficulty several hours after exposure to the antigen. Chronic form can lead to pulmonary insufficiency.