Alopecia Areata Incognita

Alopecia areata incognita (AAI) is a type of diffuse alopecia that causes acute hair shedding and pronounced thinning of the scalp in women, without signs of acute telogen effluvium. Clinical examination reveals reduced hair density, especially on the androgen dependent scalp, and a positive pull test for telogen roots at varying maturity stages. Trichoscopy shows yellow dots and short regrowing hairs, but no dystrophic hairs typical for diffuse alopecia areata. The prognosis for AAI is generally favorable with a rapid response to steroid treatment. AAI is more common in patients with androgenetic alopecia due to the shortening of the hair cycle, which reduces the number of follicles with high mitotic activity and increases the number of follicles with low mitotic activity that shift to telogen instead of becoming dystrophic, resulting in diffuse and telogenic hair loss.