Keloids are raised overgrowths of scar tissue that occur at the site of a skin injury. They occur where trauma, surgery, blisters, vaccinations, acne or body piercing have injured the skin. Less commonly, keloids may form in places where the skin has not had a visible injury. Keloids differ from normal mature scars in composition and size. Some people are prone to keloid formation and may develop them in several places.
To continue reading this article, you must login
Subscribe to Harvard Health Online for immediate access to health news and information from Harvard Medical School.