Patients with profuse hair shedding may reveal anagen hair dystrophy: a diagnostic clue of alopecia areata incognita

Background Several patients, especially women, seek advice because of hair loss. They may be diagnosed clinically as having telogen effluvium (TE) or androgenetic alopecia (AGA), but histopathology may reveal that a proportion of them have in fact alopecia areata incognita (AAI). Objectives To detect dystrophic anagen hairs in such patients. Methods We studied 1932 patients with hair loss and no signs of classical alopecia areata. They were submitted to the modified wash test (which counts the total number of telogen hairs lost and the percentage of vellus hairs) and divided into patients having pure TE (403), patients with AGA + TE (1235) and patients with pure AGA (294). Dystrophic hairs were detected with a low magnification microscope. Results Dystrophic hairs were observed in 13 patients with TE (3.2%), in 54 with AGA + TE (4.4%) and in none with AGA. In addition, 7 patients with TE and 32 with AGA + TE developed small patches of alopecia areata in 6 to 9 weeks. No patches developed in patients with AGA. Conclusions The presence of dystrophic hairs and the development of patches of alopecia areata (and their absence in pure AGA) provide a first evidence of the possibility that within the heterogenous condition named TE some patients have in fact AAI.