Trauma-Associated Subungual Exostosis of the Hallux in a 10-Year-Old Girl Presenting with Persistent Pain and Progressive Onychodystrophy: A Case Report

Subungual exostosis is an uncommon benign osteocartilaginous growth arising from the distal phalanx, most often affecting the great toe and frequently presenting with pain, nail plate elevation, and secondary nail deformity. Delayed recognition is common because early clinical findings may mimic more prevalent nail disorders. We report a 10-year-old previously healthy girl who presented with an 8-month history of persistent throbbing pain at the right great toe nail unit that began after direct trauma. Symptoms progressively worsened and were exacerbated by pressure and footwear. Examination revealed a firm, fixed, exquisitely tender subungual nodule with yellow discoloration of the nail plate, elevation, and onycholysis. Plain radiography demonstrated a well-corticated bony outgrowth arising from the tip of the terminal phalanx of the right hallux, consistent with subungual exostosis. The patient was investigated and counseled regarding definitive surgical management and follow-up. This case highlights the importance of considering subungual exostosis in children with chronic post-traumatic onychalgia and evolving nail dystrophy, and it underscores the diagnostic value of early radiography to avoid prolonged symptoms and inappropriate treatments.