Cutaneous sarcoidosis during interferon alfa and ribavirin treatment of hepatitis C virus infection: two cases.

Interferon-induced sarcoidosis is well documented. We report two new cases of sarcoidosis in two patients with hepatitis C virus infection treated with interferon alfa and ribavirin. These patients developed cutaneous sarcoidosis about 3 months after the beginning of the combination therapy. Spontaneous regression of the lesions was noted after discontinuation of the treatment. There have been more than 20 observations of the appearance or aggravation of this granulomatosis with interferon alfa and more recently with the combination of interferon alfa plus ribavirin. Dermatological signs are found in 50% of cases, and are often diagnostic. Other clinical symptoms of sarcoidosis resemble side-effects of interferon. The evolution is fairly stereotypical and is marked by a regression of the lesions following a dose reduction or curtailment of interferon. Interferon alfa acts by stimulating the T-helper (Th) 1 immune response. In addition to its antiviral action, ribavirin also enhances the Th1 response. Indeed, the superiority of the combination of interferon alfa and ribavirin in terms of antiviral action is corroborated by the enhancement of a Th1-type immune reaction by this combination. At the same time, this immune cell reaction triggers a greater granulomatous reaction.