Longitudinal course of extrinsic allergic alveolitis in pigeon breeders.

The purpose of this study was to assess the longitudinal course of pigeon breeders' disease by evaluating 24 patients with the acute form of the disease 10 years after their original diagnosis. Twenty one patients attended for clinical assessment, pulmonary function studies, chest radiography, and antibody measurement. Eighteen had continued to keep pigeons, emphasising their commitment to the hobby. Despite continued antigen exposure pigeon related symptoms had improved in most patients and only five still had troublesome symptoms. Four patients had residual abnormalities of pulmonary function or chest radiographs and three had chronic bronchitis. Fanciers had attempted to regulate their exposure to the birds by use of masks and by spending less time in their lofts but this is an unlikely explanation for the benign course of their disease, as levels of antibody to pigeon gammaglobulin remained high, suggesting that appreciable antigen exposure was still occurring. In most cases a state of equilibrium between host and antigen appeared to have developed. This observation has implications for the clinical management and understanding of the nature of the disease.