Scars are areas of fibrous tissue that replace normal skin after injury. Thus, scarring is a natural part of the healing process. With the exception of very minor lesions, every wound (including surgery) results in some degree of scarring. Scarring injuries can cause depressions in the skin surface (atrophic scars) such as those formed as the result of acne, surgery, stretch marks, burns, injuries or infections. Other times they can form a hypertrophic (thickened or raised) scar or keloid as a result of too much scar tissue in the wound.
What are keloid scars?
Keloid scars are firm, smooth, hard growths due to spontaneous scar formation. They can arise soon after an injury, or develop months later. Keloids may be uncomfortable or itchy, and may be much larger than the original wound. Keloids may form on any part of the body, although the upper chest and shoulders are especially prone to them.
The precise reason that wound healing sometimes leads to keloid formation is under investigation but is not yet clear.
While most people never form keloids, others develop them after minor injuries, burns, insect bites and acne spots. Dark skinned people form keloids more easily than Caucasians.
Keloids are harmless to general health and do not change into skin cancers.
What are hypertrophic scars?
As wounds heal, scar tissue forms, which at first is often red and somewhat prominent. Over several months, a scar usually becomes flat and pale. If there is a lot of tension on a healing wound, the healing area is rather thicker than usual. This is known as a hypertrophic scar.
What are Atrophic Scars?
Atrophic scars look like small dents or pits in the skin. They are rarely of a regular shape, and tend to be jagged around the edges. Most people will have one or two atrophic scars following acne or chicken pox.
Atrophic scars are related to the underlying tissues beneath the scar. If these structures are in anyway damaged it is likely that you will end up with some form of atrophic scar as the skin reacts to changes below. These tissues could be muscle or fat, and in order for your scar to be raised, these will need to be treated first.