Trichoscopic findings of alopecia areata include black dotsDots are small, round structures of less than 0.1 mm in diameter that have a red color when corresponding to blood vessels; however, when due to melanin, their color ranges from black, brown, to blue-gray depending on the depth and concentration of the melanin in the skin (Tyndall effect)., broken hairs, exclamation mark hairs, tapered hairs, Pohl-Pinkus constrictions, yellow dots, short vellus hairs, upright regrowing hairs and pigtail hairs .
Trichoscopic feature Reported prevalence in %* (mean value**) Yellow dots 6 - 100 (62) Black dots 0 - 84 (53) Exclamation mark hairs 12 - 71 (39) Tapered hairs 5 - 81 (51) Broken hairs 0 - 71 (49) Short vellus hairs 34 - 100 (61) Upright regrowing hairs 11 - 96 (23) Pigtail (circle) hairs 4 - 61 (21) Pohl-Pinkus constrictions 2 - 10 (4) Adapted from Waśkiel et al. 
Active hair loss in alopecia areata is characterized by presence of black dots, broken hairs, exclamation mark hairs, tapered hairs and Pohl-Pinkus constrictions [6, 7]   . In long-lasting, non-active disease mainly yellow dots and short vellus hairs are observed . Good response to the therapy of alopecia areata is characterized the reduction followed by the loss of exclamation mark hairs, broken hairs and black dots . Yellow dots are the least responsive . In initial hair regrowth, increased number of short vellus hairs is observed. With the continuation of the therapy they are substituted by fully pigmented terminal hairs so a decreased number of short vellus hairs may be detected . Hair regrowth is characterized by presence of upright regrowing hairs and pigtail hairs .Big text
4. Rudnicka, L., et al., TrichoscopyThis glossary term has not yet been described. update 2011. J Dermatol Case Rep, 2011. 5(4): p. 82-8. 5. Waskiel, A., et al., Trichoscopy of alopecia areata: An update. J Dermatol, 2018. 6. Guttikonda, A.S., et al., Evaluation of Clinical Significance of DermoscopyThe examination of [skin lesions] with a 'dermatoscope'. This traditionally consists of a magnifier (typically x10), a non-polarised light source, a transparent plate and a liquid medium between the instrument and the skin, and allows inspection of skin lesions unobstructed by skin surface reflections. Modern dermatoscopes dispense with the use of liquid medium and instead use polarised light to cancel out skin surface reflections. in Alopecia Areata. Indian J Dermatol, 2016. 61(6): p. 628-633. 7. Inui, S., et al., Clinical significance of dermoscopyThe examination of [skin lesions] with a 'dermatoscope'. This traditionally consists of a magnifier (typically x10), a non-polarised light source, a transparent plate and a liquid medium between the instrument and the skin, and allows inspection of skin lesions unobstructed by skin surface reflections. Modern dermatoscopes dispense with the use of liquid medium and instead use polarised light to cancel out skin surface reflections. in alopecia areata: analysis of 300 cases. Int J Dermatol, 2008. 47(7): p. 688-93. 8. Kibar, M., et al., Trichoscopic findings in alopecia areata and their relation to disease activity, severity and clinical subtype in Turkish patients. Australas J Dermatol, 2015. 56(1): p. e1-6. 9. Inui, S., T. Nakajima, and S. Itami, Coudability hairs: a revisited sign of alopecia areata assessed by trichoscopyThis glossary term has not yet been described.. Clin Exp Dermatol, 2010. 35(4): p. 361-5. 10. Rudnicka, L., M. Olszewska, and A. Rakowska, Atlas of trichoscopy: dermoscopy in hair and scalp disease. 2012, London: Springer. 11. Ganjoo, S. and D.M. Thappa, Dermoscopic evaluation of therapeutic response to an intralesional corticosteroid in the treatment of alopecia areata. Indian J Dermatol Venereol Leprol, 2013. 79(3): p. 408-17. 12. El Taieb, M.A., et al., Platelets rich plasma versus minoxidil 5% in treatment of alopecia areata: A trichoscopic evaluation. Dermatol Ther, 2017. 30(1).