Nearly Complete Hair Re-Pigmentation in an Older Patient Treated with Hydroxyurea for Essential Thrombocytosis

A 77-year-old woman with essential thrombocytosis experienced nearly complete hair re-pigmentation from gray to dark brown after 20 weeks of low-dose hydroxyurea treatment, without using hair dye or supplements. This unexpected side effect was accompanied by melanoderma, melanonychia, and onychodystrophy. The patient was monitored without intervention as she was pleased with the hair color change, and her platelet count remained well-controlled. The case suggests that hydroxyurea may activate melanocytes, leading to hair color restoration, indicating potential therapeutic and aesthetic uses for this medication class.