Livedoid vasculitis and central nervous system involvement in systemic lupus erythematosus.

Of 66 patients with systemic lupus erythematosus (SLE), 11 (16.7%) had livedoid vasculitis. The sites of predilection included the elbows, knees, fingers, soles, and back, which are not those of common livedoid vasculitis. Livedoid vasculitis developed in ten (90.9%) of the 11 patients with SLE who eventually developed central nervous system (CNS) lupus. In contrast, such preceding livedoid vasculitis occurred in only three (11.5%) of the 26 patients with severe nephrotic lupus nephritis. Livedoid vasculitis did not occur in any patient with neither CNS lupus nor severe lupus nephritis. These results indicate that livedoid vasculitis in SLE is a very important cutaneous manifestation that may possibly be prodromal to CNS lupus.