A clinical and histopathologic study included 24 patients with trichotillomania involving the scalp, who were seen at the Mayo Clinic in the three-year period from 1968 through 1970. The disorder occurred most frequently in children and tended to be chronic, the average duration of the hair loss being 4½ years at the time of consultation. In our series, trichotillomania indicated a minor neurotic trait in some cases and was associated with more serious mental disorder in others. The histopathologic findings in trichotillomania are characteristic of the diagnosis and may be useful in confirming the clinical diagnosis. The presence of catagen hairs, the absence of significant inflammation or scarring, and the presence of keratin plugs and dilated follicular infundibula are among the important findings seen in the review of the scalp biopsy specimens.
Muller SA, Winkelmann RK. TrichotillomaniaA Clinicopathologic Study of 24 Cases. Arch Dermatol. 1972;105(4):535-540. doi:10.1001/archderm.1972.01620070007003