Comma hairs: A dermatoscopic marker for tinea capitis. A rapid diagnostic method

Background: Dermatoscopy and videodermatoscopy have been used for several years in the diagnosis of skin disorders. Objective: We sought to determine whether tinea capitis (TC) shows characteristic videodermatoscopy features that may facilitate its differentiation from alopecia areata (AA). Methods: Two patients with TC caused by Microsporum canis, confirmed by mycological culture and fluorescence under Wood lamp, were examined with videodermatoscopy and results were compared with videodermatoscopy results of 12 patients with AA. Results: The distinctive and most prominent feature of TC was presence of commalike structures (comma hairs). These were accompanied by broken and dystrophic hairs. Videodermatoscopy features of AA included exclamation mark hairs, vellus and dystrophic/cadaverized hairs, and yellow dots corresponding to hyperkeratotic hair follicle plugs. Limitations: This study was conducted on two patients, both with M canis infection. Conclusions: Comma hairs were observed as a distinctive videodermatoscopy feature of M canis-induced TC. This finding was not observed in AA, typified generally by exclamation mark hairs.