OBJECTIVE To determine the responsibility of hepatitis B virus (HBV) and hepatitis C virus (HCV) and therapeutic implications in a patient who developed systemic vasculitis.

CASE REPORT The case of a 38 year old woman who had a past history of addiction to intravenous drugs and developed systemic vasculitis after infection by HBV and HCV is described. The clinical and laboratory findings substantiated not only the diagnosis of polyarteritis nodosa (PAN) but also that of mixed cryoglobulinaemia with a monoclonal IgMκ component.

CONCLUSION Because cryoglobulins are rarely found in HBV related PAN but often associated with HCV infection, and in light of the histological findings, cryoglobulinaemia was interpreted as being secondary to HCV infection. This example of a highly complex situation emphasises the need to gather all relevant clinical, biological, histological, and complementary data so that the best treatment for overlapping of distinct vasculitides can be selected.