Ruxolitinib as a Targeted Therapy for Arthritis and Alopecia Universalis in a Child with APECED: A Case Report

Background Autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy (APECED) is a rare monogenic autoimmune disorder caused by mutations in the AIRE gene and is characterized by immune dysregulation with multi-organ involvement. While several case reports in adults have demonstrated the successful use of Janus kinase (JAK) inhibitor in controlling autoimmune complications, its use in the pediatric age group remains poorly documented, particularly in the setting of concomitant rheumatologic and dermatologic manifestations. Case Presentation We report an 11-year-old boy with APECED who initially presented at the age of 3 years with alopecia universalis. At 5 years of age, he developed primary hypoparathyroidism and adrenal insufficiency. In 2020, the diagnosis of APECED was confirmed by genetic testing, which revealed a homozygous frameshift variant in the AIRE gene (c.1193del; p.Pro398Argfs*82). Subsequently, he developed nail pitting and dystrophy, recurrent episodes of oral candidiasis, and bilateral nephrocalcinosis. At 10 years of age, he presented to the pediatric rheumatology clinic with symmetrical arthritis involving both wrists and the right knee, associated with pain and swelling. A clinical diagnosis of arthritis was made, with further investigations pending. He was initiated on ruxolitinib at a dose of 5 mg twice daily, which led to gradual improvement in joint symptoms. After three months, the dose was increased to 10 mg twice daily, resulting in marked clinical improvement of arthritis and noticeable regrowth of scalp hair and eyebrows. Residual bilateral limitation of wrist extension persisted. Methotrexate was subsequently added to further optimize arthritis control. Of note, he had 2 episodes of oral candidiasis since he was started on ruxolitinib, both resolved with oral nystatin. Conclusion This case demonstrates the potential therapeutic benefit and favorable safety profile of ruxolitinib in a pediatric patient with APECED, leading to improvement of both arthritis and alopecia universalis.