Immune phenotyping impacts on management of severe cutaneous adverse reaction

Purpose of review Pathogenesis of severe cutaneous adverse reaction (SCAR) including Stevens–Johnson syndrome (SJS)/toxic epidermal necrolysis (TEN) and drug-induced hypersensitivity syndrome/drug reaction with eosinophilia and systemic symptoms (DIHS/DRESS) has been identified by recent studies. This review provides recent understanding of pathomechanisms of SCAR and how to manage the patients with SCAR. Recent findings Recent studies, including single-cell data, identified key signaling pathways and immune phenotypes in SCAR. These studies have highlighted potential treatments, such as TNF-α inhibitors and JAK inhibitors. Moreover, severity score of DIHS/DRESS and many biomarkers for SCAR are provided. Summary The pathogenesis of SCAR remains unclear, and most effective therapeutic strategy has not yet been established. However, the pathogenesis of keratinocyte cell death in SJS/TEN, which is the most critical phenomenon, has been established. The difference of immune profile between early and late stage have been suggested in DIHS/DRESS. Although new therapeutic options have been identified by resent studies, there is a lack of trial data for the efficiency of them. Further trials and studies of SCAR is expected to lead to the development of general effective treatment options for SCAR.