[Alpha interferon-induced eczema in atopic patients infected by hepatitis C virus: 4 case reports].

OBJECTIVES: We report four cases of eczema induced by alpha interferon in atopic patients treated for chronic hepatitis C. CASE REPORTS: Eczema developed in 4 patients with certain (3 cases) or possible (1 case) atopy treated by subcutaneous injections of alpha interferon for hepatitis C virus infections. Delay to onset was 3 weeks to 6 months. Interferon was highly likely the causal agent: lesions started at site of interferon injection, followed the rhythm of interferon injections (three cases), disappeared at interferon withdrawal. In two patients, the lesions diffused to other sites. Both Introna and Roféron were used. Three patients also took ribavirine. The possible role of a contact factor (antiseptic.) was ruled out. Skin tests (patch tests, prick tests, intradermal reactions) were negative for interferon alpha and for a standard battery. DISCUSSION: The role of interferon in the induction of skin diseases or its influence on the course of certain dermatoses is well known. In atopic patients, interferon might induce eczema via an immunomodulator rather than an allergic mechanism since skin tests (performed in one patient) were negative. This observation is similar to that in psoriasis induced by interferon in predisposed subjects who develop skin lesions at injection sites which sometimes diffuse to distant localizations. The role of other factors (hepatitis C virus infection, ribavirine) remains unknown; they might participate in this mechanism by aggravating skin dryness.