Are there distinct clinical and pathological features distinguishing idiopathic from drug-induced subacute cutaneous lupus erythematosus? A European retrospective multicenter study.

Abstract

Clinical and pathologic criteria to distinguish drug-induced subacute lupus erythematosus (DI-SCLE) from idiopathic (I-SCLE) are controversial. The aim of the survey was a retrospective analysis of a consistent number of iatrogenous and idiopathic SCLE cases, by means of clinical and histopathologic investigation. Eleven European university dermatology units collected all diagnosed cases from January 2000 to December 2016. Board-certified dermatopathologists reviewed the histopathologic specimens. Statistical analysis included Student t test, exact test of goodness-of-fit, Fisher's exact test, and the Cochran-Mantel-Haenszel test for repeated measures. Out of 232 patients, 67 (29%) belonged to the DI-SCLE group. Patients with DI-SCLE were significantly older and reported more systemic symptoms than those with I-SCLE. No statistical differences were found for presentation pattern or serology, while histopathology showed a significant association of mucin deposition (P = .000083), direct immunofluorescence positivity for granular immunoglobulin M, and C3 deposits on the basement membrane zone (P = .0041) for I-SCLE and of leukocytoclastic vasculitis (P = .0018) for DI-SCLE. This is a retrospective study. An integrated clinical and immunopathologic evaluation is useful to differentiate I-SCLE from DI-SCLE. Older age at onset and more frequent systemic symptoms characterize DI-SCLE. Mucin deposition and immunofluorescence findings are found in I-SCLE, and leukocytoclastic vasculitis is found in DI-SCLE.