Causes of Hypopigmentation

Mature scars often appear hypopigmented compared to surrounding normal skin. The most common explanation of the hypopigmentation is that the areas affected have decreased melanocyte numbers compared to the surrounding skin. However, recent immunohisto-chemical analyses by Velangi et al demonstrated preservation of epidermal melanocytes within scar tissue. Their findings raise the possibility that hypopigmentation of scars may not simply be due to a decrease in melanocyte number but rather an optical effect due to alterations in collagen and microvasculature. These studies also laid the theoretical foundation for using lasers and phototherapy devices to repigment scars.