Trichotillomania: a histopathologic study in sixty-six patients.

This report reviews the results of scalp biopsies in 66 (38%) of 174 patients with trichotillomania seen at the Mayo Clinic from 1978 through 1988. The most important findings included catagen hairs in 74%, pigment casts in 61%, and traumatized hair bulbs in 21%. Bulbar inflammation and atrophic anagen hairs were not seen. The most characteristic features most often were noted in specimens from areas that had been affected for usually less than 8 weeks. It is important to examine many sections stained with hematoxylin and eosin because only a few sections may show the characteristic changes. The study points out the usefulness of scalp biopsy for making or excluding a diagnosis of trichotillomania.