Concurrent localized scleroderma and discoid lupus erythematosus. Cutaneous 'mixed' or 'overlap' syndrome

Four patients with concurrent, chronic, progessive, localized scleroderma and discoid lupus erythematosus were studied; the condition originated as linear scleroderma in three of them. Three of the four patients were young females at the onset of the first skin disease. Dermatopathologic study confirmed the scleroderma and lupus erythematosus (LE). Direct immunofluorescence showed a positive band test in three cases. Unusual serological results included a positive LE clot test in three cases, a positive extractable nuclear antigen test in one case, and a negative antinuclear antibody test on repeated occasions in all four cases. Rare cutaneous disease similar to systemic, "mixed," or "overlap" connective tissue disease exists and offers an opportunity to study unusual immunologic and pathological events in both scleroderma and LE.