Men and women can get stretch marks on several parts of their bodies, including the belly, thighs, hips, breasts , upper arms, and lower back. The marks form in the dermis, the middle layer of skin that allows it to retain its shape. When constantly stretched, the dermis can break down, leaving stretch marks behind.
This kind of scarring happens when skin doesn’t bounce back after it’s been stretched by pregnancy, weight gain, or extreme weight loss. The marks often start off looking reddish or purplish and then become glossy, making the skin appear to be streaked in silver or white.