Extrinsic alíergic alveolitis (EAA) belongs to the family of interstitial lung diseases. It results from repea-ted inhalation of causative antigens in susceptible individuals. The two most adequately studied and best known forms of EAA are farmeťs lung and pigeon breedeťs disease. The clinical presentation of the disease has been defmed as acute, subacute and chronic. For the acute form of the disease, which oceurs seve-ral hours after the antigen challenge, an immune-complex-mediated tissue injury is typical. However, a T-cell mediated immune inflammatory response prevails in advanced stages of the disease. No commonly accepted diagnostic eriteria háve yet been published. The most important step is to consider EAA in the differential diagnosis of any interstitial lung disease and to review the patienťs oceupational and environmen-tal history. There are no pathognomic clinical, radiographic, laboratory or histologie abnormalities for EAA. Avoidance of sensitising antigen is the key element of the treatment regime. Corticosteroids are recommended in acute, severe and progressive disease. Acute pigeon breedeťs disease appears to háve favorable prognosis. Patients with progressive and irreversible pulmonary damage háve a fairly high risk of death.

        Key words: extrinsic alíergic alveolitis, farmer's lung, pigeon breedeťs disease.