Diagnostic Accuracy of Trichoscopy in Trichotillomania: A Systematic Review

Abstract

Trichotillomania is formally classified as a mental health disorder, but it is commonly diagnosed by dermatologists. The aim of this systematic review is to assess the diagnostic value of trichoscopy in diagnosing trichotillomania. The analysis identified the 7 most specific trichoscopic features in trichotillomania. These features had the following prevalence and specificity: trichoptilosis (57.5%; 73/127 and 97.5%, respectively), v-sign (50.4%; 63/125 and 99%), hook hairs (43.1%; 28/65 and 100%), flame hairs (37.1%; 52/140 and 96.5%), coiled hairs (36.8%; 46/125 and 99.6%), tulip hairs (36.4%; 28/77 and 89.6%), and hair powder (35.6%; 42/118 and 97.9%). The 2 most common, but least specific, features were broken hairs and black dots. In conclusion, trichoscopy is a reliable new diagnostic method for hair loss caused by hair pulling. Trichoscopy should be included as a standard procedure in the differential diagnosis of trichotillomania in clinical practice.

Keywords: dermatoscopy; dermoscopy; hair-pulling disorder; trichoscopy; trichotillomania.

Fig. 1

Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) flowchart. *Excluded records: reviews, book chapters, articles in languages other than English, case reports, articles concerning animals, articles concerning different diseases. **Excluded articles: 1 article was based on a number of patches instead of patients, 3 articles did not present the frequency of trichoscopic findings, 1 article contained an unclear data considering trichoscopic findings, 1 article described trichotemnomania instead of trichotillomania. ***10 original studies and 3 case series.

Fig. 2

The 7 most characteristic trichoscopic features of trichotillomania (×70). (a) Hook hairs: partly coiled hairs with a hook-like appearance. (b) Coiled hairs: irregularly coiled hairs with a jagged end. (c) V-sign: created when 2 or more hairs emerging from 1 follicular unit are pulled simultaneously and break at the same length above scalp surface. (d) Hair powder: residue of totally damaged hair shafts. (e) Trichoptilosis: longitudinal splitting of the distal end of hair shaft (f) Flame hairs: hair residues, semi-transparent, wavy, and cone-shaped, resembling a fire flame. (g) Tulip hairs: short hairs with a tulip leaf-like hyperpigmentation at the distal end.