There is a growing understanding of the different syndromes that have a definite, and in some cases a possible, association with viral infections. Hepatitis C virus-associated mixed cryoglobulinemias and hepatitis B virus-associated polyarteritis nodosa are examples of a vasculitis with a definite viral association. However, various types of cutaneous vasculitis are examples of a vasculitis with only a possible association with a viral infection.