title: A New Subtype of Lichen Planopilaris Affecting Vellus Hairs and Clinically Mimicking Androgenetic Alopecia.
abstract: BACKGROUND
  Lichen planopilaris (LPP) is a follicular variant of lichen planus. A new subtype of LPP mimicking androgenetic alopecia (AGA) may be misdiagnosed. Inappropriate medical therapy or hair transplantation may exacerbate this subtype.
  
  
  OBJECTIVE
  To introduce clinicopathologic findings of a new subtype of LPP that selectively affects vellus hair in the pattern of AGA.
  
  
  METHODS
  In a cross-sectional study, 433 (66.6%) men and 217 (33.4%) women with alopecia who were candidates of medical treatment or hair transplantation were included. Gross and microscopic attributes of their diseases were investigated.
  
  
  RESULTS
  Among the total of 650 patients, 58 (8.9%; 95% confidence interval, 6.7%-11.1%) patients, including 52 women and 6 men, had LPP. We identified a distinct category of LPP presenting with diffuse hair loss in the pattern of AGA with predominant terminal hair, significant decrease in vellus hair, and minute punctuate scars in histopathology. Vellus hair follicles were the main sites of involvement. Perifollicular fibrosis and mild fibrosis with lichenoid lymphocytic infiltration around infundibular area of vellus hair follicles were present.
  
  
  CONCLUSIONS
  There is a new form of LPP with clinical features similar to AGA. This form is histopathologically similar to LPP but selectively affects vellus hair follicles.
authors.affiliation: *American Board of Hair Restoration Surgery, Department of Dermatology, Abbasi Hair Clinic, Tehran, Iran; †Department of Dermatopathology, Razi Hospital, Tehran University of Medical Science, Tehran, Iran; ‡Department of Dermatology, Rasoul-e-Akram Hospital, Iran University of Medical Sciences, Tehran, Iran; §Department of Dermatology, Abbasi Hair Clinic, Tehran, Iran.
authors.forename: Ali
authors.initials: A
authors.lastname: Abbasi
authors.forename: Kambiz
authors.initials: K
authors.lastname: Kamyab-Hesari
authors.forename: Ramin
authors.initials: R
authors.lastname: Rabbani
authors.forename: Farzaneh
authors.initials: F
authors.lastname: Mollaee
authors.forename: Sheida
authors.initials: S
authors.lastname: Abbasi
mesh_terms: D000328:Adult; D000368:Aged; D000505:Alopecia / Q000175:diagnosis; D001706:Biopsy; D003430:Cross-Sectional Studies; D003937:Diagnosis, Differential; D005260:Female; D018859:Hair Follicle / Q000473:pathology; D006801:Humans; D008010:Lichen Planus / Q000145:classification / Q000175:diagnosis* / Q000473:pathology; D008297:Male; D008875:Middle Aged; D012535:Scalp / Q000473:pathology