Stretch marks are narrow streaks or lines that occur on the surface of the skin.
Doctors often refer to stretch marks as stria, striae or – during pregnancy – striae gravidarum.
The tummy (abdomen), buttocks, breasts and thighs are the areas of the body most often affected.
Stretch marks are often red or purple to start with, before gradually fading to a silvery-white colour. They're usually long and thin.
Read more about the characteristics of stretch marks.
What causes stretch marks?
Stretch marks are the result of the skin suddenly stretching. The middle layer of skin (dermis) breaks in places, allowing the deeper layers to show through.
The dermis can be stretched:
Read more about the causes of stretch marks.
When to see your GP
See your GP if you have stretch marks that don't seem to be linked to weight gain or growth, because they may be due to another condition.
In rare cases, stretch marks are caused by syndromes such as Cushing’s syndrome or Marfan syndrome, or from the overuse of powerful steroid creams or ointments on the skin.
Treating stretch marks
Most stretch marks aren't particularly noticeable and will fade over time.
If you have unsightly stretch marks, or if they affect a large area of your body, you may want to try one of the treatment options available.
Creams, gels, lotions, laser surgery and cosmetic surgery are all used to treat stretch marks. However, there's little medical evidence to show that these treatments are particularly effective, so it's important to be realistic about what they can achieve.
It should also be noted that laser treatment and cosmetic surgery for stretch marks aren't available on the NHS, and private treatment can be expensive.
Read more about treating stretch marks.
Preventing stretch marks
In certain situations, such as during pregnancy, it isn't possible to prevent stretch marks.
However, maintaining a healthy weight and looking after your skin can reduce your risk of getting them.
Read more about preventing stretch marks.