Sarah Demouche

and 6 more

Background: Since the 2002 SCAR study, erythema multiforme(EM), a post-infectious disease, has been distinguished from Stevens-Johnson syndrome (SJS), drug-induced. Nevertheless, EM cases are still reported in the French pharmacovigilance database (FPDB). Objectives: To describe EM reported in the FPDB and to compare the characteristics of the reports. Methods: This retrospective observational study selected all EM cases reported in the FPDB over two periods: period 1 (P1, 2008-2009) and period 2 (P2, 2018-2019). Inclusion criteria were 1) a diagnosis of clinically typical EM and/or one validated by a dermatologist; 2) a reported date of onset of the reaction; and 3) a precise chronology of drug exposure. Cases were classified confirmed EM (typical acral target lesions and/or validation by a dermatologist) and possible EM (not-otherwise-specified target lesions, isolated mucosal involvement, doubtful with SJS). We concluded possible drug-induced EM when EM was confirmed, with onset ranging from 5 to 28 days without an alternative cause. Results: Among 182 selected reports, 140(77%) were analyzed. Of these, 67(48%) presented a more likely alternative diagnosis than EM. Of the 73 reports of EM cases finally included (P1, n=41; P2, n=32), 36(49%) had a probable non-drug cause and 28(38%) were associated with only drugs with an onset time ≤4 days and/or ≥ 29 days. Possible drug-induced EM was retained in 9 cases (6% of evaluable reports). Conclusions: This study suggests that possible drug-induced EM is rare. Many reports describe “polymorphic” rashes inappropriately concluded as EM or post-infectious EM with unsuitable drug accountability subject to protopathic bias.