Skin diseases associated with hepatitis C virus infection.

Hepatitis C virus (HCV) is a bloodborne agent transmitted by apparent and inapparent parenteral procedures representing a frequent cause of liver disease world-wide. Both acute and chronic HCV infection may affect the liver as well as various non-hepatic tissues. Numerous extrahepatic disorders have been recognised in association with HCV infection among which dermatological diseases occupy a central part. Cutaneous necrotising vasculitis, mixed cryoglobulinemia, porphyria cutanea tarda and lichen planus are the major skin diseases frequently associated with HCV infection, but other skin disorders, such as Adamantiadis-Behçet syndrome, erythema multiforme and nodosum, malacoplakia, urticaria and pruritus, may also be linked to hepatitis C. Further studies are necessary to establish or refute an aetiopathogenetic role of HCV in these conditions. Skin manifestations are also part of the clinical picture of other extrahepatic disorders associated with HCV infection, such as thyroid dysfunction and HCV-related thrombocytopenia. The response to interferon alpha (alpha-IFN) therapy in skin diseases is unpredictable with some patients ameliorating, others remaining stationary and others deteriorating.