Unusual cutaneous manifestations of systemic lupus erythematosus: I. Urticaria-like lesions. Correlation with clinical and serological abnormalities.

Ten of 143 systemic lupus erythematosus patients demonstrated urticaria-like lesions. Lesional biopsies in 7 of 9 patients tested revealed a leukocytoclastic angiitis and in 2, a mononuclear perivascular infiltrate. Direct immunofluorescent studies in 2 of 6 patients tested revealed IgM and C3 deposition in and about dermal blood vessels. Nine of the 10 systemic lupus erythematosus, patients displayed active clinical disease (e.g., arthritis, renal disease, etc.), a positive lupus band test, antibodies against deoxyribonucleic acid or Sm macromolecules, serum hypocomplementemia and markedly elevated quantities of serum immune complexes as determined by an immunoradiometric assay employing Raji cells. Similar lesions were not detected in 35 discoid lupus erythematosus patients. These studies strongly suggest: (1) urticaria-like lesions are uncommon cutaneous manifestations of systemic lupus erythematosus. (2) These urticaria-like lesions do not represent a classic IgE mediated urticaria. (3) These urticaria-like lesions generally occur in lupus erythematosus patients demonstrating clinical and/or serological evidence of systemic disease activity. (4) These lesions are probably secondary to immune complex deposition. We, therefore, conclude that all urticarial lesions in lupus erythematosus patients should be biopsied and the patient evaluated for active systemic disease.