Sarcoidlike manifestations of histoplasmosis

We have evaluated 11 patients with sarcoidosis accompanied by laboratory evidence for histoplasmosis. Clinical findings were typical of those described in sarcoidosis. Eight patients were treated with corticosteroids and responded promptly without progression of histoplasmosis. One patient received a 35 mg/kg course of amphotericin B without clinical improvement, but responded appropriately to corticosteroid therapy. Another patient had positive sputum cultures for Histoplasma capsulatum 5 years after initial diagnosis of sarcoidosis, but showed no improvement in the pulmonary infiltrate after treatment with amphotericin B. Although histoplasmosis and sarcoidosis may be interrelated in several ways, we postulate that H capsulatum may have triggered a chronic inflammatory disease recognized as sarcoidosis in some of these patients, a hypothesis yet to be tested. Alternative explanations for the association of histoplasmosis and sarcoidosis include the coincidental occurrence of two separate illnesses in a "hyperendemic" area for histoplasmosis and false-positive serologic test results caused by the heightened humoral immune response observed in sarcoidosis.