Dermoscopic Features Of Alopecia Areata And Their Significance

BackgroundAlopecia areata is a kind of sudden patchy alopecia that produces non-scarring hair loss,commonly known as "ghost shaving".Clinically,it is round or elliptical,with clear borders in the hair loss area.The scalp is normal at the skin lesions and generally had no symptoms.In general,clinical diagnosis of alopecia areata is based on typical pattern of hair loss.But due to the variability of its clinical symptoms,the diagnosis of alopecia areata may be difficult and challenging and often not easy,especially in the early stage of the disease,often need to conduct scalp biopsy.Dermoscopy is a quick,convenient,non-invasive examination that is originally used primarily for the diagnosis of pigmented skin diseases and skin tumors,but has now been expanded to evaluate other skin diseases and eventually to evaluate hair and scalp.A large number of studies have shown that the use of dermoscopy in clinical examinations have greatly improved the accuracy of diagnosis and reduce the necessity of biopsy.With the continuous improvement and update of dermoscopic technology,it is now more than just a magnifying glass,with the help of polarized light,it can observe the hair shaft shape,hair follicle opening,skin surface structure and capillaries and other aspects,help to diagnose hair and scalp diseases.ObjectiveTo explore the dermoscopic features and significance of alopecia areata and its differential diagnosis with androgenetic alopecia and healthy controls,so as to provide strong evidence for the diagnosis of alopecia areata.MethodsThe dermoscopic datas and relevant clinical datas of 31 patients with alopecia areata,28 patients with androgenetic alopecia and 26 healthy controls were collected and analyzed.The relevant datas were statistically analyzed using SPSS 19.0 software.The quantitative datas were expressed as(x±S).The ratio(%)of counting datas indicated that the chi-square test or fisher’s exact test was used to compare the positive rate of dermoscopic features between the three groups,and P<0.05 indicated that the difference was statistically significant.Bonferroni method was used for the comparison between groups,and P<0.017 indicated that the difference was statistically significant.ResultsThe most common dermoscopic features were yellow dots and short vellus hairs,which was 67.74%,followed by black dots,broken hairs,capillaries,white hairs,exclamation mark hairs,white dots,scalp pigmentation,scale increasing,brown peripilar sign and loop/spiral hair.There were statistical significant(P<0.017)between alopecia areata patients and androgenetic alopecia patients in the positive rate of yellow dots,black dots,broken hairs,exclamation mark hairs,hair diameter diversity>20%,scalp pigmentation,increased single follicle units and scale increasing.Among them,the positive rates of yellow dots,black dots,broken hairs and exclamation mark hairs were significantly higher in patients with alopecia areata than in patients with androgenetic alopecia.The positive rates of yellow dots,black dots,broken hairs,exclamation mark hairs,short vellus hairs and capillaries were significantly higher in patients with alopecia areata than healthy controls(P<0.017).ConclusionThe main dermoscopic features of alopecia areata were yellow dots,short vellus hairs,black dots,broken hairs and exclamation mark hairs,which were of important clinical significance to the diagnosis of alopecia areata.Among them,the yellow dots,short vellus hairs,and black dots were sensitive for diagnosing alopecia areata.The yellow dots,and black dots,broken hairs and exclamation mark hairs were specific for diagnosing alopecia areata.