Darkening of skin or pigmentation of the underarm and intimate area is a common and sometimes embarrassing condition. There are many factors contributing to the presence of underarm pigmentation and intimate area such as hormonal changes, high dose of niacin, birth control pills. Underarm pigment can also be the result of external causes such as use of deodorant, shaving and frequent use of depilatory creams, excessive sweating, build-up of dead skin cells and friction from shaving or clothing.