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

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.