Quantitative Analysis on the Scalp Hair Characteristics in Koreans using Phototrichogram

Yoo, Jae Hak; Park, Hyung Yoon; Park, Tae Ho; Kim, Kea Jeung

Abstract

BACKGROUND: Although the diagnosis of hair disease depends on the comparison of normal and abnormal findings, data on normal hair characteristics in Koreans have not been reported. We have developed some technical improvements on phototrichogram methodology to assess hair characteristics.
OBJECTIVE
This study was performed to quantify Koreans' hair characteristics at each site(eg. vertex, occipital, temporal) of the scalp according to the age and sex using the phototrichogram and to compare the differences of hair characteristics between Caucasian and Korean population.
METHODS
Hairs in the precisely defined circle at each(vertex, temporal, occipital) area of the scalp in 42 healthy volunteers(16 men and 26 women) were evaluated according to sex and age groups, respectively. Each circumscribed area of the scalp, centered with a dot tattoo to ensure reproducibility, were first shaved: The shaven area was first photographed just after shaving. Two days later, grouping pattern of grouped hair unit, total and anagen hair counts were determined from low magnification image. The linear hair growth rate(micrometer/day) and hair shaft diameter were obtained from high magnification image.
RESULTS
The results can be summarized as follows: 1. The range of hair density was 119+/-13/cm2~137+/-12/cm2 in male and 92+/-24/cm2~139+/-23/cm2 in female. Hair density of the occiput was significantly higher than that of temple. 2. The range of linear hair growth rate was 300+/-19micrometer/day~319+/-27micrometer/day in males and 289+/-17micrometer/day~327+/-54micrometer/day in females. Hair growth rate in each group decreased in order of vertex, occiput and temple. Most of the hairs on the vertex in older males have slower growth rate than in other groups. 3. The range of hair thickness was 70+/-6micrometer~89+/-10micrometer in males and 75+/-7micrometer~87+/-6micrometer in females. Hairs of the vertex in the older male group(age>or=45 year-old) were thinner than those of the occiput. The population of thin hair(<40micrometer) on the vertex in older males was 7.6% larger than that of other sites. 4. The range of anagen ratio was 91.0% ~ 93.7% in males and 91.9%~94.1% in females.
CONCLUSIONS
Lower hair density, larger hair diameter and slower hair growth rate were remarkable in Koreans than in Caucasian. In addition, considering the hair characteristics of Koreans, the newer, improved method of phototrichogram will be a promising tool in the study of the hair disease including androgenetic alopecia, and in the quantitative analysis of the effects of agents stimulating hair growth.