A Case of Black Dot Ringworm Caused by Trichophyton violaceum

Lee, Jae Bong; Kwon, Kyung Sool; Chung, Tae Ahn; Jang, Ho Sun; Oh, Chang Keun

Abstract

Tinea capitis is a dermatophytosis of the scalp and associated hairs that is caused by the species of genera Mecrosporum and Trichophyton. It commonly affects children. Black dot ringworm (BDR) can be caused by Trichophyton tonsurans and Trichophyton violaceum. We report a 82-year-old woman with diffuse hair loss and black dots on the frontal scalp, and an erythematous annular scaly patches on the forehead. Endothrix invasion of the hair was shown on the 20% KOH mount. In fungus culture, slow growing violaceous verrucous colonies were obtained from the scalp and face. Microscopic findings revealed irregular branching hyphae and numerous chlamydospores. Histologic findings of the scalp showed numerous PAS positive fungal elements in the hair. Griseofulvin was administrated at the dose of daily 1000mg for 3 weeks, but no clinical and mycological improvement were obtained and tenderness and pustules were developed. Terbinafine at the dose of daily 250mg was administrated for 6 weeks, and clinical and mycologic improvement were obtained and damaged scalp hairs were replaced by intact hair shaft. There has been no recurrence for 8 months. To our best knowledge, this is the first case of BDR caused by T. violaceum in the Korean literature.