Supplementary Material for: Beyond the Scalp: Bilateral Hand Trichoteiromania Revealed by Trichoscopy - A Case Report

Introduction: Trichoteiromania is a friction-induced hair-shaft disorder caused by repetitive rubbing/scratching and is often considered the hair-shaft expression of lichen simplex chronicus ("scratching-pseudoalopecia"). It is classically described on the scalp and presents with lichenified plaques and characteristic trichoscopy such as broom hairs and V-hairs. Pruritus or an urge to rub is common and may help distinguish it from trichotillomania (hair pulling), which is often asymptomatic. To date, the condition has been described almost exclusively as a scalp disorder. Case Presentation: We report a 55-year-old man working in finance with a 15-year history of asymptomatic skin changes on the dorsal hands, initially unilateral and later bilateral, who was referred because of concern about malignancy. Examination revealed symmetric lichenified plaques with excoriations, erythema, haemorrhagic crusts, and numerous short broken hairs on the dorsal aspects of the index fingers and thumb, as well as bilateral enlarged lunulae of the thumbnails. Trichoscopy was diagnostic, showing broom hairs, V-shaped hairs, short broken hairs at different lengths, perifollicular and interfollicular scale, and irregular perifollicular brown pigmentation, consistent with trichoteiromania. No biopsy was required. The patient was reassured regarding the benign nature of the condition, started on topical urea and clobetasol, and referred for psychiatric follow-up to address the underlying compulsive rubbing behaviour. Conclusion: This case represents, to our knowledge, the first description of trichoteiromania affecting a non-scalp site and demonstrates that its full trichoscopic signature can occur on extracranial hair-bearing skin. This case expands the anatomical spectrum of trichoteiromania beyond the scalp and highlights trichoscopy as a rapid, non-invasive tool to attribute hair-shaft damage to chronic friction.