Nocardia asteroides sinusitis. Presentation as a trimethoprim-sulfamethoxazole responsive fever of unknown origin.

A patient with a yearlong fever of unknown origin responded to trimethoprim-sulfamethoxazole and was discovered to have culture-proved Nocardia asteroides sinusitis, with absence of detectable disease in other organs. An inhalational route is postulated as the mode of entry of the organism, with localization in the maxillary sinus.