[Bird breeder's lung in children].

A case of hypersensitivity pneumonitis due to pigeon-dropping antigens is reported in a 9 year old girl, and compared with other seven previous reports in children. The insidious nature of this disease, as well as the importance of detailed environmental information in children with unexplained respiratory disease are emphasized. In this case, lung function tests showed a classic restrictive ventilatory defect, and a serious obstructive ventilatory defect evidenced in the narrowing of the smaller airways, and a reduction in the forced expiratory flow at small lung volumes. Hypersensitivity pneumonitis is a lung disease that results from sensitization by inhalation of a variety of organic dusts. Patients usually have circulating antibodies against the etiologic agents. Most patients with this disease also have sensitized T-cells to these agents. Long-term exposure can lead to irreversible lung disease. The histopathologic features are chronic interstitial and alveolar inflammation frequently accompanied by a granulomatous response. The most common symptomatic features are fever, chills and dyspnea 4 to 8 hours after exposure. Antibody activity to antigens is detected in the serum of both symptomatic and asymptomatic breeder's lung. Cellular hypersensitivity to antigens is demonstrated "in vitro" with peripheral lymphocyte populations in almost all symptomatic patients.