Systemic sarcoidosis presenting as a granulomatous tattoo reaction secondary to interferon-alpha treatment for chronic hepatitis C and review of the literature.

Sarcoidosis is a multisystem granulomatous disease of unknown etiology. Immune alterations involving heightened T-helper-1 responses have been proposed to play a major role in the pathogenesis of sarcoidosis. Interferon-alpha therapy and hepatitis C infection have been implicated in the development of a variety of autoimmune diseases. However, despite the wide use of IFN-alpha therapy for hepatitis C, only a few cases of sarcoidosis have been reported in this context. We report the case of a 42-year-old white female with hepatitis C, who developed systemic sarcoidosis shortly after therapy with IFN-alpha2b. The disease was heralded by the appearance of a cutaneous sarcoid/ foreign body granulomatous reaction at the site of an old tattoo. The sarcoidosis responded to a short course of oral prednisone therapy. We also reviewed the other reported cases and discussed the possible immunological mechanisms involved.