Lupus erythematosus panniculitis.

LE panniculitis is an uncommon but distinctive subset of LE. It may develop in patients with discoid LE or SLE or may occur as an isolated phenomenon. The typical clinical presentation is that of multiple indurated nodules or plaques (or both), often associated with lipoatrophy, there being a predilection for the proximal extremities and trunk. Because the clinical and histologic findings of LE panniculitis overlap with those of other connective tissue diseases, evaluation of patients suspected of having LE panniculitis should include a complete history and physical examination as well as serologic studies, determination of peripheral blood counts, and tests of renal function. A deep excisional biopsy rather than punch biopsy should be performed for diagnosis. The characteristic histologic pattern includes hyaline necrosis of fat; lymphoid nodules, often with germinal centers; and lymphocytic lobular panniculitis. Direct immunofluorescence testing of skin may help confirm the diagnosis in patients who have less than classic histologic features. LE panniculitis tends to have a chronic course marked by recurrent nodules or plaques (or both). Antimalarial agents, with or without courses of systemic steroids, are beneficial in most patients.