Trichoscopy criteria for diagnosing female androgenic alopecia.

Differential diagnosis of chronic hair loss remains a challenge in dermatology. The aim of the study was to evaluate the value of a new scalp visualization technique, trichoscopy, in differential diagnosis of hair loss. Trichoscopy was performed in 131 females (59 with androgenic alopecia, 33 with chronic telogen effluvium, 39 healthy controls). Based study results, a standardized trichoscopy report was developed and diagnostic criteria for female androgenic alopecia were established. Major criteria: increased number of yellow dots and thin hairs, as well as decreased average hair thickness in frontal area. Minor criteria: increased frontal area to occiput ratio of single-hair units (>2:1), vellus hairs (>1.5:1) and follicles with perifollicular discoloration (>3:1) Fulfillments of 2 major criteria or 1 major and 2 minor is diagnostic for female androgenic alopecia with a 92% specificity. In conclusion, trichoscopy is the first method which allows differential diagnosis of hair loss and establishing the diagnosis of female androgenic alopecia