P28 COMPARATIVE EVALUATION BETWEEN ANDROGENETIC ALOPECIA AND NORMAL SCALP BY PHOTOTRICHOGRAM
Yoo JH, Kim TH, Park TH, Kim KJ
Department of Dermatology, KangBuk Samsung Hospital, SungKyunKwan University, Korea

Background: Human hair usually emerges from the scalp in groups of 2 or 3-hair units. Hair densities and grouping patterns in androgenetic alopecia (AGA) patients are known to be different from those in normal adults. Objective: This study was performed to quantify Koreans' hair characteristics at each site (vertex, occipital, temporal) of the scalp according to the age and to compare the differences of hair characteristics of AGA and normal adults using phototrichogram. Methods: Hairs in the precisely defined circle at each (vertex, temporal, occipital) site of the scalp in 37 AGA male patients and 15 healthy male volunteers were evaluated according to age. Each circumscribed area of the scalp, centered with a dot tattoo to ensure reproducibility, was photographed just after shaving, and two days later. Results: The results can be summarized as follows: 1. In normal adult males, the range of hair density was 117±13/cm2 ~ 140±16/cm2, with the hair density of the occiput being significantly higher than that of the temple. In AGA male patients, the range of hair density was 102±23/cm2 ~ 137±17/cm2. 2. The numbers of grouped hair units per square centimeter in the non-bald adult male group ranged from 59±11/? to 73±14/?. The most common grouped hair unit was a 2-hair unit, followed by a 1-hair unit and a 3-hair unit group. In the AGA group, the most common grouped hair unit was a 1-hair unit, followed by a 2-hair unit and a 3-hair unit group. Conclusions: Based on the data about hair density and hair grouping patterns in AGA patients, surgeons can estimate the most probable number of follicular units in hair transplantation procedures.