Medical professionals often refer to stretch marks as Stria, Striae or throughout pregnancy, Striae Gravidarum. Stretch marks are initially red and purple in colour; however, over time can become silver and white. Stretch marks tend to be long and thin.
A person suffers from stretch marks after the skin has been stretched over a short period of time. This can happen after pregnancy, rapid weight gain or loss and puberty. The stretching causes the middle layer of the skin (the dermis) to tear, which allows the deeper layers of the skin to present themselves. The dermis consists of durable inter-connected fibres that allow your skin to stretch as your body changes. When the body changes at a rapid rate, the fibres within the dermis break. The breaks in the fibres allow the blood vessels to appear, which causes the initial redness. Over time, the blood vessels will lessen and the fat beneath the skin shows. This is why the stretch marks then become white.
Stretch marks are known to be hereditary. If a close family member such as a parent suffers from stretch marks, then it is very likely that you will develop them yourself.
Both men and women can gain stretch marks; however, it is most common in women.