Hepatitis C infection: a systemic disease with extrahepatic manifestations.

Mixed cryoglobulinemia, renal syndromes, lymphoproliferative disorders, Sjögren syndrome, porphyria cutanea tarda, and neuropathies are all strongly associated with hepatitis C virus (HCV) infection. Diabetes, thyroid disease, and the presence of autoantibodies in the serum are also linked to HCV, but less strongly. The pathophysiologic basis for most of these syndromes seems immunologic. Cirrhosis and chronic HCV infection seem to be risk factors.