Azathioprine-Induced Alopecia Totalis and Knuckle Hyperpigmentation in a Child with Uveitis: Test Before You Leap!

A 13-year-old girl with non-infectious panuveitis developed alopecia totalis and knuckle hyperpigmentation due to azathioprine-induced myelosuppression. Genetic testing revealed a homozygous variant in the NUDT15 gene, which is linked to azathioprine toxicity. After discontinuing azathioprine and starting alternative treatments, her blood counts normalized, and her hair and skin conditions improved. This case highlights the importance of monitoring for alopecia and knuckle hyperpigmentation as early indicators of azathioprine toxicity, especially in settings where genetic testing is not feasible. Regular blood count monitoring is recommended to prevent severe complications.