Stretch marks (stria or striae) are the result of skin suddenly stretching, typically during pregnancy, as a result of weight gain or due to growth spurts during puberty.
Narrow red or purple streaks or lines occur on the surface of the skin where the middle layer of skin (dermis) breaks in places, allowing the deeper layers to show through, often on the abdomen, buttocks, breasts and thighs. These can fade to a silvery-white colour over time.
