Immediate exacerbation of atopic dermatitis after switching from upadacitinib to dupilumab: A report of two cases

Abstract Janus kinase (JAK) inhibitors are efficacious for atopic dermatitis (AD). However, some patients receiving JAK inhibitors develop acne, especially younger patients, or herpes zoster, especially elderly patients, and desire to switch to dupilumab. We experienced two patients with immediate exacerbation of AD after switching from upadacitinib to dupilumab, and herein report these cases. This phenomenon is attributed to the difference in elimination half‐life of the two drugs and a slower onset of efficacy of dupilumab than upadacitinib. When switching from a JAK inhibitor to dupilumab, short‐term concomitant use, intensifying topical treatment, and/or rescue with cyclosporine should be considered.