Farmer's lung in early childhood.

A 5-year-old child with classic farmer's lung disease is reported. The disease started after a flulike episode and progressed during 3 months to severe respiratory failure. The clinical features were fatigability, weight loss, recurrent fever, dry cough, pulmonary rales, and clubbing. Serologic studies for precipitins to Micropolyspora faeni were positive. The chest roentgenogram showed a ground-glass appearance with air bronchogram. The open lung biopsy material was typical for alveolitis, with minute interstitial granulomas and obliteration of lung parenchyma. The child's condition improved rapidly with prednisone therapy and avoidance of the allergen.