A stretch mark is a type of scar that develops when our skin stretches or shrinks quickly. The abrupt change causes the collagen and elastin, which support our skin, to rupture. As the skin heals, stretch marks may appear. When stretch marks first appear, they tend to be red, purple, pink, reddish-brown, or dark brown, depending on your skin colour. Early stretch marks may feel slightly raised and can be itchy. In time, the colour fades and the narrow bands sink beneath your skin. If you run your finger over a mature stretch mark, you often feel a slight depression.