Erythema induratum and active pulmonary tuberculosis.

The etiology of erythema induratum, a rare disease of the skin in the United States but occasionally seen in natives of Asian countries, remains a source of debate. Its association with tuberculosis, although strongly suspected for more than one century, has not been clearly defined. We report a case of erythema induratum occurring in a young Chinese woman in the setting of active pulmonary tuberculosis. Both diseases promptly responded to antituberculous therapy. The diagnosis of erythema induratum should urge the clinician to search for a source of active tuberculosis, and treatment should be initiated accordingly.