Focal Atrichia: A Diagnostic Clue in Female Pattern Hair Loss

Abstract Background Focal atrichia is a common clinical finding in female pattern hair loss whose specificity and histologic findings need further clarification. Objective To determine the frequency of focal atrichia in various types of hair loss and its histologic characteristics in female pattern hair loss. Methods Part 1: Review of 250 consecutive female patients seen with hair loss for the presence of focal atrichia and Part 2: paired biopsies of haired areas vs focal atrichia in 18 subjects with female pattern hair loss Results Focal atrichia was seen in 46/104 (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 Biopsy findings of focal atrichia in female pattern hair loss showed primarily a more progressive miniaturization process than that of haired areas of the scalp. Limitations Some women with female pattern hair loss may have had concomitant chronic telogen effluvium Conclusions When present, focal atrichia is a clinical clue to the diagnosis of female pattern hair loss, particularly late onset subtype.