Comparative Evaluation of Hair Density and Grouped Hair Unit Pattern Between Androgenetic Alopecia and Normal Scalp

The study aimed to compare the hair density and grouped hair unit pattern between individuals with androgenetic alopecia (AGA) and those with a normal scalp. The researchers evaluated hairs in specific areas of the scalp in 37 AGA male patients and 15 healthy male volunteers. They found that in normal adult males, the hair density ranged from 117 to 140 hairs per square centimeter, with the occiput having a significantly higher density than the temple. In AGA patients, the hair density ranged from 102 to 137 hairs per square centimeter, and the differences between the vertex and occiput were statistically significant. The most common grouped hair unit in both groups was a 2-hair unit, followed by a 1-hair unit and a 3-hair unit group. The AGA group had a lower hair density and a larger proportion of 1-grouped hair units compared to the normal adult male group. This information can be useful for surgeons in estimating the area of donor scalp for hair transplantation procedures.