A scar is a patch or line of tissue that remains after a wound has healed.
Scars are a natural part of the healing process and they can happen both inside and outside the body. Visible scars sometimes form after the skin has been broken, but you can also have scars on your internal organs, for example, where a cut has been made during surgery.
How does a scar form?
When a wound occurs and there is a break in some of the tissue in the body, the body heals it by producing more of a protein called collagen. Collagen builds up at the place where the tissue is broken, eventually helping to close it.
New collagen continues to form and then break down in the site of the wound for years afterwards. The scar gradually becomes smoother and softer.
Scars on the skin can take up to two years to fade, but after this time it is unlikely that they will fade any more.
Where do scars tend to form?
Certain areas of the body are more likely to have scars than others. The knees and shoulders often have more visible scars, perhaps because they need to move and stretch a lot during the healing process. Darker skin is also more likely to scar.
When are scars abnormal?
Sometimes abnormal scars develop:
- A hypertrophic scar is a red, raised scar that may form when healing goes on for too long.
- A keloid is an overgrowth of tissue when too much collagen is produced at the site of the wound and the scar keeps growing even after the wound has healed.
