RESUMEN
We report here 3 cases of chronic bird fancier's lung diagnosed immunologically using antibodies to pigeon dropping extract. None of the patients were bird fanciers but had indirect exposure to birds in their living environment, and had been using feather-filled duvets or pillows for a long time. Two of 3 cases were positive for environmental provocation tests and 2 cases had pathological findings of hypersensitivity pneumonitis such as multinucleated giant cells and non-necrotizing epithelioid cell granulomas. One case was resistant to steroid therapy alone and was successfully treated by coadministration of prednisolone and cyclosporin A. Another case was treated by steroid alone but died of acute exacerbation of unknown cause. These cases suggest that not only feathers but two or more kinds of bird-related antigens were involved in the sensitization immunology and development of bird fancier's disease, and that clinicians should perform thorough history taking with environmental surveillance relevant to birds.