Hepatitis C virus and lichen planus: A case-control study of 340 patients.

Lichen planus (LP) has been associated with liver disease, particularly hepatitis C virus (HCV) infection, in several studies to date. Most of these reports, especially the larger series, were conducted in Europe. In addition, the type of LP associated with HCV was reported to be oral LP in most studies. We conducted a case-control study in a US metropolitan population known to have a low seroprevalence of HCV infection to explore the impact of geography and endemicity of HCV on the association between cutaneous LP and HCV. The study comprised 340 patients with cutaneous LP (as case ) against 577 patients with psoriasis (as control-1 ). Hepatitis antibody titers and liver function abnormalities were our main outcome measures. Prevalence of HCV antibody among 149,756 regional volunteer blood donors (as control-2 ) was also used for comparison. Twelve (55%) of 22 patients with LP tested for HCV were antibody positive. This was significantly higher than 25% of 40 psoriasis patients tested for HCV antibody (P =.04) or than 0.17% of blood donors tested for HCV antibody (P < 10(-5)). Thus a small but significant percentage of US patients with cutaneous LP had HCV antibody. Because LP may be the first presentation of HCV infection, it is important for clinicians to actively look for such infection in patients with LP.