The extrahepatic manifestations of hepatitis C were reviewed in the November issue of Cleveland Clinic Journal of Medicine. The review points out that cryoglobulinemia is the most strongly associated manifestation. Most cases of what was formerly called essential mixed cryoglobulinemia are in fact due to hepatitis C. Most patients with circulating cryoglobulins are asymptomatic, with about 10% manifesting the typical features of purpura, arthralgia, renal disease and neuropathy, according to the review.
Other disease associations mentioned were Sjogren syndrome (an autoimmune exocrinitis differing from classic Sjogren syndrome in the lack of antibodies to SSA/Ro and SSB/La), lymphoproliferative disorders, prophyria cutanea tarda and membranoproliferative glomerulonephritis (which can occur with or without cryoglobulinemia).
Antiviral treatment for the underlying hepatitis C seems to be the most effective treatment for cryoglobulinemia and some of the other manifestations.