We should be aware that HP may be caused by F. napiforme in the home environment.

An episode of fever, cough, shortness of breath and leucocytosis developed in a 31-year-old atopic housewife from mould exposure in her home environment is evaluated. A chest radiograph revealed diffuse tiny nodular infiltrations in both whole lung fields. Spirometry revealed a severe restrictive type of ventilation impairment. Bronchoalveolar lavage (BAL) showed an increased lymphocyte count with reversed CD4+/CD8+ ratio and transbronchial lung biopsy showed markedly increased lymphocytic infiltration in alveolar septa. Fungal cultures in the air of her home were positive for Penicillium expansum and other fungi. Double immunodiffusion test with the patient's serum showed two precipitin bands to P. expansum antigens. Her symptoms, abnormal findings of radiograph, and spirometric abnormalities disappeared after 2 months' avoidance. The serum precipitin disappeared after 1 month's avoidance. This study indicates that the patient had hypersensitivity pneumonitis (HP) on exposure to P. expansum in her home environment.