Skin nontumor


Androgenic alopecia

Editorial Board Member: Robert E. LeBlanc, M.D.
Editor-in-Chief: Debra L. Zynger, M.D.
Jasmine Saleh, M.D., M.P.H.
Jodi Speiser, M.D.

Last author update: 6 May 2021
Last staff update: 26 April 2023

Copyright: 2020-2023,, Inc.

PubMed Search: Androgenic alopecia [title] pathology

Jasmine Saleh, M.D., M.P.H.
Jodi Speiser, M.D.
Page views in 2022: 4,803
Page views in 2023 to date: 2,530
Cite this page: Saleh J, Speiser J. Androgenic alopecia. website. Accessed June 1st, 2023.
Definition / general
Essential features
  • Scalp
Clinical features
  • Polygenetic condition with varying severity, rate of progression, age of onset and affected scalp sites (BMJ 1998;317:865)
  • Men: hair loss typically involves the temporal and vertex region while sparing the occipital region; the hairline also recedes to form a characteristic “M” shape (BMJ 1998;317:865)
  • Women: diffuse thinning of the frontal / parietal scalp with retention of the frontal hairline (Int J Womens Dermatol 2018;4:203)
  • Has been associated with several other medical conditions:
  • Hair pull test is normal (Int J Womens Health 2013;5:541)
  • Male pattern baldness (Norwood-Hamilton classification) (Endotext: Male Androgenetic Alopecia [Accessed 8 July 2020])
    • Type I: minimal bitemporal recession of hair
    • Type II: extension of type I
    • Type III: hair loss in tonsure area and recession of hair from the forehead
    • Type IV - VI: extension of type III
    • Type VII: most severe pattern of hair loss, with a confluence of the balding areas; hair preserved only around the back and the sides of the head
  • Female pattern baldness (Ludwig classification) (Int J Womens Dermatol 2018;4:203)
    • Type I: mild (hair loss on the front and top of the scalp with relative preservation of the frontal hairline)
    • Type II: moderate
    • Type III: severe
  • Scalp biopsy
Case reports
Clinical images

Images hosted on other servers:

Hair shaft diameter variability

Microscopic (histologic) description
Microscopic (histologic) images

Contributed by Jodi Speiser, M.D.

Vertical section of scalp biopsy

Positive stains
Sample pathology report
  • Skin, left scalp, punch biopsy:
    • Nonscarring alopecia (see comment)
    • Comment: Histological sections show a decrease in hair follicles with a mild periadnexal lymphocytic infiltrate around the upper third of the hair follicle. No peribulbar inflammation is present in the sections examined. There are increased vellus hairs present. Some sections show prominent sebaceous glands. PAS stain shows normal basement membrane thickness and EVG stain shows preservation of elastic fibers. These findings are consistent with androgenic alopecia.
Differential diagnosis
  • Telogen effluvium:
    • Increased telogen hairs without follicular miniaturization
  • Alopecia areata:
    • Uniformly miniaturized follicles with less variation in hair size
    • Lower terminal to vellus and anagen to catagen ratios compared to androgenic alopecia
    • Peribulbar lymphocytic infiltrate
  • Traumatic alopecia (traction alopecia / trichotillomania):
    • Melanin pigment casts and trichomalacia with increased catagen hairs and no follicular miniaturization
  • Cicatricial alopecia:
    • Follicular scars with absent elastic fibers
  • Fibrosing alopecia in a pattern distribution:
    • Lichenoid inflammatory infiltrate in the upper follicle region, peripilar casts and loss of follicular openings
  • Syphilis:
    • Superficial and deep perivascular and perifollicular lymphoplasmacytic infiltrate and sometimes necrotizing pustular folliculitis
Board review style question #1

Which of the following is true about androgenic alopecia?

  1. No association with several other medical conditions
  2. Positive hair pull test
  3. Progressive miniaturization with varying size of the hair follicles
  4. Scarring alopecia
Board review style answer #1
C. Progressive miniaturization with varying size of the hair follicles

Comment Here

Reference: Androgenic alopecia
Board review style question #2
Which of the following features is observed in androgenic alopecia?

  1. Increased number of terminal hair follicles
  2. No fibrous tracts
  3. No hair miniaturization
  4. Reduced terminal to vellus ratio of 4:1 or less
Board review style answer #2
D. Reduced terminal to vellus ratio of 4:1 or less

Comment Here

Reference: Androgenic alopecia
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