Capillaritis associated with interferon-alfa treatment of chronic hepatitis C infection

We report the case of a 36-year-old man who was referred with an asymptomatic eruption that started on both lower legs. This started shortly after being commenced on interferon-alfa for chronic hepatitis secondary to hepatitis C. Clinically, the eruption was consistent with a capillaritis (pigmented purpuric dermatosis). Histology confirmed this to be lymphocytic vasculitis. Lymphocytic vasculitis is frequently identified in the salivary glands of patients who are hepatitis C positive. Although leukocytoclastic vasculitis confined to the skin is frequently reported with hepatitis C, lymphocytic vasculitis is rarely reported. We consider that the lymphocytic vasculitis in our patient occurred as a result of interferon-alfa treatment because of the strong temporal relationship between the onset of the skin eruption and drug therapy. (J Am Acad Dermatol 2000;43:937-8.)