Skin diseases associated with hepatitis C virus: facts and controversies.

Hepatitis C virus (HCV) is a common infectious agent and may induce several systemic disorders like mixed cryoglobulinemia. In the geographic areas where HCV infection is hyperendemic, HCV is the predominant etiologic factor for porphyria cutanea tarda and lichen planus. Vasculitides and autoimmune disorders, such as sicca syndrome, are probably often related to the virus. Interferon-a2b, which is largely used in the treatment of HCV-positive patients, may induce cell-mediated autoimmune side effects. Dermatologists may help to identify those patients timely.