Hair Shaft Fracture in a Young Athlete: A Rare Case Report of Acquired Trichorrhexis Nodosa.

Trichorrhexis nodosa (TN) is a hair shaft anomaly characterized by abnormal fragility and weak points (nodes) in the hair shaft. It can be congenital or acquired, with the acquired form being more common. Patients typically present with lusterless and fragile hair, an inability to grow hair to a normal length, fraying at the distal free end, and white knots and fractures along the hair shaft. This condition is often linked to daily hair care routines and exposure to chemicals or environmental factors that cause trauma to the hair. Diagnosis is typically confirmed through dermoscopy or microscopy, which reveal characteristic paintbrush-like hair fractures. Hair anomalies in sports have been rarely documented. Here, we report a unique case of acquired distal TN in a 19-year-old male professional volleyball player and a recreational swimmer with exposure to multiple environmental factors such as years of chlorine water exposure and training that may have contributed to this condition. The patient presented with a three-month history of abnormal hair fragility and glistening white areas along the hair shafts. Trichoscopy revealed multiple white nodes along the hair shafts, while light microscopy displayed nodular swellings with disruption of the cuticle and splaying out of cortical fibers. Scanning electron microscopy (SEM) further demonstrated the classical "two brooms stuck in opposite direction" or "paintbrush fracture" appearance. Based on the clinical presentation and microscopic findings, a diagnosis of diffuse distal acquired TN was made. The patient was advised to tonsure his head and use gentle, sulfate-free shampoo for regrown hair. Follow-up at six months showed no recurrence of lesions, highlighting the importance of identifying and addressing potential causative factors in managing this condition.