Clubbing in hypersensitivity pneumonitis. Its prevalence and possible prognostic role.

To know the prevalence and prognostic significance of finger clubbing in hypersensitivity pneumonitis induced by avian antigen, this physical sign was evaluated in 82 patients who were followed up from 1 to 5 years (mean, 2.6 years). According to clinical, roentgenographic, and functional criteria, the patients were classified in one of three stages at admission as well as at least 1 year later. Digital clubbing was retrospectively recorded as present or absent by physical examination. Our results showed that 44 patients (51%) included in this study presented clubbing at the time of diagnosis. Sixteen of these patients presented with worsening of their lung disease, whereas only 5 of the 38 patients without clubbing incurred a worsening of their condition. This finding suggests that digital clubbing is frequent in pigeon breeder's disease and may help to predict clinical deterioration.