Childhood hypersensitivity pneumonitis probably caused by cat hair.

A case is reported of a 10-y-old boy with hypersensitivity pneumonitis probably caused by his cat. Hypersensitivity pneumonitis caused by animal hairs is reported in furriers, but hypersensitivity pneumonitis in children has only been described as caused by birds, moulds or other fungi. Steroid treatment may interfere with the possibility of finding the causative antigen.