Dupilumab facial redness: histologic characterization on a series of four cases

Lay abstract Dupilumab is an advanced treatment for atopic dermatitis. The new appearance of a peculiar head and neck dermatitis may be observed in as many as 4-10% of subjects receiving this drug, though it was not reported in the course of the clinical trials that led to the approval of dupilumab. Out of 62 adults treated with dupilumab for atopic dermatitis in the authors' Dermatology Clinic, four subjects (6%) were observed to have head and neck dermatitis. The condition appeared between 8 and 24 weeks after initiation of dupilumab and lasted 8 to 12 weeks. The four subjects gave permission to perform a skin biopsy. Microscopic analysis of their samples suggested that this peculiar facial redness may be a drug-induced reaction associated with dupilumab, although its causes and mechanisms still require understanding.Dupilumab-related head and neck dermatitis is an increasingly reported clinical manifestation occurring in 4-10% of patients on dupilumab that was apparently not reported in clinical trials. Out of 62 adult patients treated with dupilumab for atopic dermatitis in the authors' center, four cases (6%) of head and neck dermatitis were observed, for which a skin biopsy was obtained. Onset occurred between 8 and 24 weeks after initiation of dupilumab, and the reaction resolved after 8-12 weeks. Histopathology and immunohistochemical findings support the authors' hypothesis that facial redness may be a toxic effect induced by dupilumab, although its pathogenesis still requires further investigation.