Case Report: Repigmentation and complete hair regrowth in an 11-year-old preadolescent with alopecia totalis treated with a JAK inhibitor.

Alopecia areata (AA) is an autoimmune disease characterized by non-scarring hair loss. Janus kinase (JAK) inhibitors have emerged as effective therapeutic options for severe pediatric AA, though repigmentation of white hair during treatment remains rarely reported. Herein, we report an unusual case of complete hair regeneration with simultaneous white-to-black hair conversion in a child with severe AA following JAK inhibitor therapy. An 11-year-old girl presented with alopecia totalis (AT) persisting for two years. She initially received baricitinib for seven months, achieving SALT 65% with predominantly white and gray hair regrowth. After switching to ritlecitinib 50 mg/day, black hair emerged at 6 weeks, with complete hair regrowth and repigmentation at 6 months (SALT 0). The patient has now completed 12 months of ritlecitinib therapy with sustained response and stable pigmentation. Family Dermatology Life Quality Index (FDLQI) decreased from 18 to 4. No significant adverse effects were observed. This case suggests that prolonged JAK inhibition may facilitate both hair regrowth and pigment restoration in pediatric severe AA.