Case Report: JAK1 inhibition after dupilumab discontinuation in pediatric atopic dermatitis complicated by pre-existing or emerging vitiligo.

Background: Atopic dermatitis (AD) and vitiligo are pediatric immune-mediated inflammatory skin diseases with distinct but potentially overlapping immune mechanisms. Dupilumab targets interleukin (IL)-4 and IL-13 signaling and is effective for moderate-to-severe AD. However, the coexistence, emergence, or progression of vitiligo during dupilumab therapy may create therapeutic challenges when both eczematous inflammation and melanocyte-directed autoimmunity require control. Methods: We retrospectively reviewed four children aged 6-11 years with AD complicated by pre-existing or emerging vitiligo during dupilumab therapy. Clinical features, timing of vitiligo onset or progression, response to dupilumab, subsequent targeted treatment, follow-up outcomes, and safety data were summarized. Vitiligo was diagnosed clinically and supported by Wood's lamp examination when available. Results: Two patients had vitiligo before dupilumab initiation, whereas two developed hypopigmented or depigmented lesions during dupilumab treatment. One patient with severe AD showed no obvious improvement after dupilumab; instead, original eczematous lesions became more erythematous and swollen, and new hypopigmented patches appeared around the ankle regions. Dupilumab was discontinued in all patients. Three patients were switched directly to a Janus kinase (JAK) 1 inhibitor. One patient was initially switched to a JAK3/TEC family kinase inhibitor but later changed to a JAK1 inhibitor because of AD recurrence. During follow-up, all patients showed improvement of AD and stabilization or repigmentation of vitiligo. No serious adverse events were observed. Conclusion: This case series describes a pediatric AD-vitiligo overlap phenotype in which final transition to JAK1 inhibition was associated with improvement of both diseases after dupilumab discontinuation. Causality between dupilumab and vitiligo cannot be established. JAK1 inhibition may be considered in carefully selected children requiring simultaneous control of AD and active vitiligo.