Histopathologic comparison of the subsets of lupus erythematosus.

A recent study by Bangert et al suggests that there are quantitative histologic differences that distinguish discoid lupus erythematosus (DLE) and subacute cutaneous lupus erythematosus (SCLE). Utilizing criteria proposed by these authors, we examined 77 biopsy specimens from 63 patients with various forms of lupus erythematosus, but we were unable to predict the correct clinical subset. Using the clinical diagnosis of DLE as a positive reference standard, the sensitivity and specificity for the overall pathologic diagnosis of DLE were 55% and 42%, respectively. Statistically significant histologic factors favoring the diagnosis of DLE over SCLE in the present study were pilosebaceous atrophy, hyperkeratosis, parakeratosis, basement membrane thickening around the follicles, subepidermal edema, and vascular ectasia. These histologic variables were entered into a forward stepwise multivariate regression analysis to determine distinct predictors of DLE vs SCLE. This analysis showed that pilosebaceous atrophy was the only distinct significant predictor of DLE vs SCLE. These results suggest that the histologic differentiation of clinically defined DLE and SCLE cannot be established from the histologic features examined.