Lupus erythematosus tumidus--a neglected subset of cutaneous Lupus erythematosus: report of 40 cases.

BACKGROUND Lupus erythematosus tumidus (LET) is characterized clinically by erythematous, succulent, edematous, nonscarring plaques in sun-exposed areas. Results of histological examination show perivascular and periadnexal lymphocytic infiltration and interstitial mucin deposition. The main differential diagnoses are polymorphous light eruption, Jessner's lymphocytic infiltration of the skin, reticular erythematous mucinosis, and pseudolymphoma. Since its first description in 1930, LET has been documented rarely in the literature, and its clinical importance has not been fully appreciated. OBSERVATIONS We characterized 40 patients with clinical and histological features of LET observed at our department from 1984 through 1998. The onset of the disease clustered in summer because of sun exposure, and 28 (70%) of the patients showed a remarkable photosensitivity confirmed by results of provocative phototesting. A complete resolution of the skin lesions was seen after systemic therapy with antimalarials and, in some cases, with local corticosteroids or spontaneously without any treatment. In 4 (10%) of the patients, antinuclear antibodies were detected; however, there was no evidence of underlying systemic involvement in any of the patients. CONCLUSIONS Our data constitute the largest number of patients with LET collected until now. The clinical picture, extreme photosensitivity, histological findings, and effective treatment with antimalarials are so characteristic that LET should be considered as a separate entity and differentiated from other variants of cutaneous LE. Arch Dermatol. 2000;136:1033-1041