Relevance of trichoscopy in the differential diagnosis of alopecia: A cross-sectional study from North India

Abstract

Trichoscopy is an office tool used in the diagnosis of alopecia but its utility has not been assessed. To compare the trichoscopic characteristics of different types of alopecia, identify features of diagnostic value, and to determine the utility of trichoscopy in the diagnosis of alopecia. A descriptive cross-sectional study was performed in patients with alopecia. After clinical assessment and relevant investigations, trichoscopy was performed using a non-polarized trichoscope (×10). The utility of trichoscopy in difficult cases of alopecia was assessed statistically. One hundred and twenty patients of alopecia (90 non-cicatricial, 30 cicatricial) were recruited. The diagnosis was made on the basis of a detailed history and clinical examination, and confirmed by biopsy and relevant investigations in difficult cases. Yellow dots (63.3%) were the most common trichoscopic feature followed by thin hair (40.8%). Among the 21 difficult cases of alopecia, trichoscopy was diagnostic in 19 (90.5%). Statistically significant features on intergroup comparison included black dots (Fischer's exact test, P< 0.001), cadaverized hair (P = 0.024), exclamation mark hair (P < 0.001) in alopecia areata; diameter diversity more than 20% (P < 0.001) and thin hair (P < 0.001) in androgenetic alopecia; broken hair of different lengths (P < 0.001), frayed hair (P < 0.001), split ends (P < 0.001) in trichotillomania; comma hair (P < 0.001) in tinea capitis and arborizing blood vessels in discoid lupus erythematosus (P = 0.012). The small number of patients in some types of alopecia was a limiting factor. Trichoscopy is useful in the differential diagnosis of alopecia. Among the various trichoscopic findings, those of diagnostic value were identified.