Abstract: 【Abstract】 A case of fibrosing alopecia in a pattern distribution （FAPD） and its clinicopathological, dermoscopic and TrichoScan features were reported to improve the understanding of FAPD. A 23-year-old male patient presented with progressive hair loss on the forehead and top of the head for 10 years, local hair thinning and softening, and occasional scalp itching. Skin examination showed diffuse sparseness of hair from the forehead to the top of the head, frontal hairline recession, focal thinning and softening of hair, some follicular keratotic papules and perifollicular erythema on the alopecic area, with no obvious scales. TrichoScan examination revealed markedly decreased hair density and increased proportions of vellus hairs. Dermoscopy showed loss of some follicular ostia and confluent white dots. Histopathological examination of the scalp showed lichenoid lymphocytic infiltration around the infundibulum and isthmus of hair follicles, concentrically layered perifollicular fibrosis, hair follicle destruction, formation of follicular micro-scars, markedly increased variation in the diameter of residual follicles, and some vellus hairs. The patient was diagnosed with FAPD. FAPD is easily misdiagnosed as androgenetic alopecia, and early diagnosis and treatment are needed.

Key words: Alopecia, Fibrosing alopecia in a pattern distribution, Androgenetic alopecia, Scarring alopecia