Clinical and immunologic features of livedo reticularis in lupus: a case-control study.

PURPOSE: We recently noticed the occurrence of both livedo and elevated anticardiolipin antibody levels in a small number of patients with lupus. The purpose of our study was two-fold: (1) to investigate whether anticardiolipin antibodies were more common in lupus patients with livedo than in those without; and (2) to determine if the features of Sneddon's syndrome (livedo and cerebrovascular disease) also were found in patients with lupus.

PATIENTS AND METHODS: In this case-control study of lupus patients without significant renal impairment, 29 patients with livedo reticularis (cases) were compared clinically and immunologically with 29 patients without livedo (controls).

RESULTS: Both groups shared many disease characteristics and were similar in age and sex. However, they differed markedly in other respects. Elevated anticardiolipin antibody levels were significantly more common in the cases. Indeed, 81% of all cases from our study sample had elevated anticardiolipin levels. A history of thrombosis and thrombocytopenia--clinical associates of the anticardiolipin antibody--was also significantly more common in cases than in controls. The relative odds of livedo reticularis were 23-fold greater in those with elevated anticardiolipin levels than in those without these antibodies. The estimated proportion of livedo-positive patients with elevated anticardiolipin antibodies in a general lupus population without significant renal impairment was 0.77.

CONCLUSION: The association between livedo reticularis and cerebrovascular disease, originally described by Sneddon in otherwise healthy individuals, also applies to lupus patients. The presence of elevated anticardiolipin antibody levels in 10 of 11 such patients suggests that the anticardiolipin antibody may be of pathogenetic importance in the manifestations of Sneddon's syndrome in lupus and also possibly in the idiopathic form of this disease.