Characterization of Residual Facial Dermatitis during Dupilumab Therapy: A Retrospective Chart Review to Delineate the Potential Role of Expanded Series Patch Testing

Background The underlying mechanisms of residual facial dermatitis on dupilumab (RFDD) in patients dupilumab therapy for atopic dermatitis are poorly understood. Objective We sought to determine the incidence of RFDD in patients receiving dupilumab and the rate of resolution of RFDD after expanded series patch testing (ESPT) and allergen avoidance. Methods This is a retrospective chart review of 80 patients with atopic dermatitis who were evaluated for RFDD after treatment with dupilumab. Expanded series patch testing findings and response to allergen avoidance were assessed in the subset of patients with RFDD who subsequently underwent ESPT while continuing to receive dupilumab. Results Forty-nine patients (61.3%) experienced facial dermatitis before initiating dupilumab. Thirty-five patients (43.8%) experienced RFDD after starting dupilumab. Of the 14 patients with RFDD who received ESPT, 92.9% had 1 or more relevant positive patch test results, with 50% of such patients being mostly to completely clear of facial dermatitis after allergen avoidance. Importantly, 50.6% of the positive reactions to allergens were not included on the North American Contact Dermatitis Group Core 80. Conclusions Many patients with RFDD benefit from patch testing and subsequent allergen avoidance. Expanded series patch testing should be offered to patients who experience RFDD after beginning dupilumab therapy to ensure that such patients have eliminated any exogenous component of their dermatitis, such as concomitant allergic contact dermatitis.