Trichoscopic Evaluation of Normative Values of Scalp Hair Density in an African Population from Nigeria: A Cross-Sectional Study.

Abstract

Background: Reports of hair density (HD) on healthy scalp of Africans is rare. Our study aimed to document normative scalp HD values in an African population.

Methods: A cross-sectional study of the healthy scalp of 909 individuals aged 5-45 years was conducted in 2023. Phototrichoscopic measurements were taken from four scalp sites (frontal, temporal, vertex and occipital). Hair parameters were compared between genders and across age groups. Data was analyzed using the IBM statistical package version 26.0.

Results: The mean age of the participants was 21.8 ± 11.02 years and they were 52.1% female. The number of hair strands (HS) from each pilosebaceous unit (PU) was 1 in 99.9% and 2 in 98% of the participants. HD ranged from 113 - 660/cm2 with a median (IQR) of 330.0 (301.0, 368.0) and was highest at the frontal scalp area. HD and total number of HS were significantly higher in all scalp sites in males (p=0.001) except for the frontal scalp site, p=0.283. HD and number of HS were highest in the fourth decade of life (median HD (IQR); 339 (301, 386), mean HS/PU; 37.09±6.96) and least in the first decade of life (median HD (IQR); 320 (292, 358), mean HS/PU; 35.18± 6.26) irrespective of the scalp site, P<0.001.

Conclusions: The hair density of Africans is high. The number of HS from each PU and HD varies with the scalp site, age and gender. These findings from the African scalp are relevant in the management of Africans who have hair loss and in those who require restoratives surgeries.