Stretch marks are the result of rapid stretching of the skin due to sudden growth or weight gain.This stretching causes the middle layer of skin (the dermis) to tear, allowing the deeper skin layers to show through, forming stretch marks.The dermis contains strong, inter-connected fibres that allow your skin to stretch as your body grows. However, rapid growth can over-stretch and break the fibres. The tears in the dermis allow the blood vessels below to show through. This is why stretch marks are often red or purple when they first appear.
When stretch marks occur -
- during pregnancy
- after rapid weight gain
- during puberty
- if you have a family history of stretch marks
- if you have an underlying health condition or a syndrome, such as Marfan syndrome
- after the prolonged or inappropriate use of corticosteroid medication
- These are discussed in more detail below.