Trichoscopic clues for diagnosis of alopecia areata and trichotillomania in Asians

BackgroundTrichoscopy has become a useful diagnostic tool for various hair and scalp diseases, including alopecia areata (AA) and trichotillomania (TTM), which are sometimes difficult to distinguish clinically. ObjectivesTo describe trichoscopic findings of AA and TTM in an Asian population and to establish diagnostic clues for these conditions. MethodsTrichoscopy was performed with a handheld dermoscope in 52 patients diagnosed with AA and 23 patients diagnosed with TTM. Trichoscopic images were then blindly evaluated. ResultsThe trichoscopic features more frequently observed in AA than in TTM included exclamation mark hairs (AA 59.6%, TTM 26.1%), tapered hairs (AA 59.6%, TTM 4.3%), yellow dots (AA 46.2%, TTM 21.7%), and angulated hairs (AA 26.9%, TTM 0%) (P<0.05). On the other hand, broken hairs of different lengths (TTM 100%, AA 3.8%), trichoptilosis (TTM 78.3%, AA 5.8%), V-sign (TTM 43.5%, AA 3.8%), flame hairs (TTM 43.5%, AA 0%), and hair powder (TTM 13%, AA 1.9%) were more commonly demonstrated in TTM than in AA (P<0.05). ConclusionsExclamation mark hairs indicate a diagnosis of AA but not pathognomonic. In addition, angulated hairs, fractured hairs forming a sharp angle along the hair shaft, appear to be typical for AA in Asians when differentiating from TTM. It is important to consider various trichoscopic findings together to establish the diagnosis of AA or TTM.