What is a stretch mark and how is it formed?

What is a stretch mark and how is it formed?
Stretch marks, otherwise known as striae, are caused by exactly what their name suggests – stretching of the skin.

By expanding and contracting, the skin’s connective tissue allows it to adapt to continuous movement of the body; but sometimes the skin has insufficient time to adjust. When the body expands faster than the covering skin, the skin tears and forms an internal wound; this then forms a scar as it heals. These scars are visible on the surface of the skin as stretch marks.

The likelihood of developing stretch marks varies according to skin type, race, age, diet and hydration of the skin.

Those most prone to stretch marks include pregnant women, body builders, adolescents undergoing sudden growth spurts, and individuals that experience rapid weight gain.