Variation in Follicular Caliber in the Setting of AGA

Androgenetic Alopecia and Anisotrichosis

Androgenetic alopecia in men and women looks similar when the scalp is examined up close with “trichoscopy.” (The actual pattern and areas of hair loss looks quite different when one examines the scalp from a distance because men first lose hair in the temples and crown whereas women lose hair in the mid scalp). Trichoscopy of androgenetic alopecia demonstrates a variation in the caliber or diameter of the hair follicles. This phenomenon is referred to as “anisotrichosis.” In the unaffected, non-balding scalp, most follicles in a given area are approximately the same diameter.

Androgenetic hair loss is associated with cell death in a region of the hair follicle known as the dermal papilla which leads to the follicle ultimately producing a thinner hair. This photo shows the scalp of a patient with androgenetic alopecia. A reduction in the caliber (diameter) of many follicles is evident.


Sewell L et al Anisotrichosis: A novel term to describe pattern alopecia. J Am Acad Dermatol 2007; 56: 856. 

Dr. Jeff Donovan is a Canadian and US board certified dermatologist specializing exclusively in hair loss. To schedule a consultation, please call the Whistler office at 604.283.1887

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