Alopecia areata: trichoscopic markers in determining disease activity

Background Trichoscopy is an important tool in detecting alopecia areata activity. Objective To determine the relation of the trichoscopic markers with alopecia areata activity. To demonstrate its discriminative capabilities in classifying alopecia areata activity. Patients and methods One hundred and thirty-seven patients (86 males and 51 females) with alopecia areata underwent dermoscopic assessment of bald patches. Hair-pulling test was used to assess disease activity. A 2×2 table of alopecia areata activity and trichoscopic marker was used to estimate sensitivity, specificity, accuracy, predictive value, and likelihood ratio. Results Trichoscopic markers commonly seen in alopecia areata were short vellus hairs (65.7%), broken hairs (56.9%), exclamation mark hairs (46.7%), and black dots (42.3%). According to disease activity, exclamation mark hairs (91.9%) and broken hairs (87.1%) were the most common markers in active disease while yellow dots (72.3%) and short vellus hairs (69.3%) were in stable disease. Exclamation mark hairs (91.9% vs. 9.3%), broken hairs (87.1% vs. 38.7%), black dots (53.2% vs. 33.3%), and triangular hairs (21.0% vs. 8.0%) were significantly higher in active compared with stable alopecia areata. The discriminative capability index reveals that exclamation mark hairs (91.9%) and broken hairs (87.1%) were the most sensitive signs. Triangular hairs (92.0%), and exclamation mark hairs (90.7%) were the most specific markers. Exclamation mark hairs and broken hairs were the most reliable markers (91.2% and 72.9%, respectively). The presence of exclamation mark hairs, triangular hairs, and broken hairs in bald patches raises the likelihood ratio of activity by 9.88, 2.65, and 2.45 times. Conclusion Exclamation mark hairs are the most important reliable marker of disease activity. Broken hairs, triangular hairs, and black dots found in bald patches increase the chance of disease activity. Other trichoscopic markers(yellow dots, pigtail hairs, short vellus hairs, and upright regrowing hairs) were useless signs in determining disease activity.