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.