Pulmonary nocardiosis in a patient treated with corticosteroid therapy.

We report a case of pulmonary nocardiosis in a 69-year-old man with rheumatoid arthritis who was receiving corticosteroid treatment. The patient received prednisolone for rheumatoid arthritis and antibiotics for his fever and pneumonia in another hospital, but the response to the therapy was poor. After admission to our hospital, he improved following treatment with imipenem/cilastatin for Nocardia asteroides. Pulmonary nocardiosis is difficult to diagnose and should be considered in the differential diagnosis, especially in an immunocompromised host.