Focal Atrichia in AGA

Focal atrichia: What does it mean? 

Focal atrichia refers to small circular areas on the scalp that are devoid of hair. These areas are typically slightly larger than a pencil eraser. 

Focal atrichia is seen in both male and female androgenetic alopecia and more common in more advanced stages. They may contain a few tiny vellus hairs if one looks closely but eventually these tiny hairs disappear over time. Hair regrowth does not occur in these areas.

Studies by Olsen and Whiting (see references below) showed that focal atrichia was present in 44% of women with female pattern hair loss, including 67% of late onset vs 15% of early onset, compared to 3/146 (2%) of those with other hair disorders. Hu and colleagues showed that focal atrichia in men with balding was associated with more advanced stages.
 

Reference

Olsen EA, et al. Focal Atrichia: A Diagnostic Clue in Female Pattern Hair Loss. J Am Acad Dermatol. 2017.

Hu R, et al. Trichoscopic findings of androgenetic alopecia and their association with disease severity. J Dermatol. 2015.