Coexistence of lichen planus and systemic lupus erythematosus.

Three cases of the simultaneous occurrence of lichen planus (LP) and systemic lupus erythematosus (SLE) are presented. Each patient had clinical, histologic, and immunopathologic LP. Additionally, each patient had clinical SLE that fulfilled the American Rheumatism Association criteria for the diagnosis of SLE. The clinical manifestations of SLE were predominantly cutaneous. The three patients had positive lupus band test and high titers of antinuclear antibodies. One patient had vitiligo in addition to SLE and LP. LP and SLE have common clinical, histologic, and immunopathologic features. It is possible that a common agent (or agents) may cause either disease or the overlap syndrome, depending on the immunogenetic predisposition of the patient.