A Comparative Cross-Sectional Study of Hair Density and Hair Shaft Diameter of Different Severities of Anterior Scalp Marginal Traction Alopecia in Women.

INTRODUCTION

Hair density (HD) studies of marginal traction alopecia (MTA) are few. We aimed to document the HD/cm2, number of hair shafts (HS) per pilosebaceous unit (PU), and HS diameter of different grades of anterior scalp margin MTA (AMTA).

METHODS

A cross-sectional descriptive study of 401 women over a 9-month period in 2023. The severity of AMTA was scored using the marginal traction alopecia severity score. Phototrichoscopic evaluation of HD/cm2, HS diameter, and number of HS per PU was done on the alopecic intertemporal, right and left temporal, and the non-alopecic right temporal and intertemporal scalp sites.

RESULTS

The HD/cm2 of the non-alopecic intertemporal scalp site ranged from 282 to 519 cm2 compared to that of the AMTA which ranged from 14 to 349/cm2, p < 0.001. With increasing severity of AMTA, there was a significant decrease in HD: grade 1 had HD of 227.56/cm2 compared to 131.22/cm2 in grade 4 at the intertemporal area, p < 0.001. HS diameter ranged from 0.0087 to 0.0200 mm in grade 1 and 0.0078-0.0100 in grade 4. Single hair units were present in 100%.

CONCLUSION

Anterior scalp marginal alopecia results in a significant reduction of HD, hair shaft diameter, and number of hair strands. Preventative education on hair care practices and hair styles is advocated.