[Bird fancier's lung--an allergic alveolitis].

BACKGROUND: Bird fancier's lung is globally the second most frequent cause of extrinsic allergic alveolitis. MATERIAL: For many years, the patient had influenza-like symptoms and developed progressing pulmonary fibrosis. Over a period of 10 years she had been exposed to up to 43 birds in the house at any one time and serum precipitates against avian proteins had been found. After sanitation of the house of birds and avian proteins, the pulmonary function has not deteriorated further in 5 years. INTERPRETATION: A thorough environmental history is essential in the diagnosis of extrinsic allergic alveolitis; at an earlier stage it would have made us think about this possible etiological factor. This could have prevented the development of permanent pulmonary fibrosis if the patient had been advised to avoid further exposure to antigens. There should be greater awareness of this disease among general practitioners as well as among chest consultants in Norway.