Scar formation can be a normal part of the healing process. In some cases scar tissue formation can be excessive. The two types of excessive scar tissue formation are known as keloid and hypertrophic scarring.
Keloids are red to purple wound scars which develop when the skin cannot switch off the healing process and collagen is continuously produced causing an over growth of collagen leaving a raised scar. Keloids are elevated fibrous scars that extend beyond the borders of the original wound, do not regress, and usually recur after excision. The term is coined from the Greek word cheloides, meaning “crab's claw.”
It is not known why keloids appear in some people and not others. While most people never form keloids, others develop them after minor injuries, even insect bites or pimples. Keloids may form on any part of the body, although the upper chest and shoulders are especially prone to them. Keloid scars are usually just a cosmetic problem but occasionally may be uncomfortable or itchy, and may be much larger than the original wound. They can arise soon after the injury, or develop months' later. Keloids are usually firm, raised, shiny, and smooth. They are often pink or red, or much darker or lighter in colour than the surrounding skin.
Traditionally, surgical removal of the scars was recommended. However, 45% to 80% of people will have a recurrence of the scar if surgery is not combined with other treatments (e.g., radiation, pressure dressings). Furthermore, the new scar can actually be larger and more prominent than the original scar.
A mainstay for both treatment and prevention is the injection of steroids such as triamcinolone directly into the scar. Steroids help prevent inflammation and promote the breakdown of collagen. This helps to make scars less raised, and to decrease pain and tenderness associated with the scar.
Laser therapy is now used to treat many types of skin problems, including keloids. It is often combined with steroid injections to give the best cosmetic result. Nd:YAG laser helps to reduce the redness of the keloids.
Silicon gel dressings are a popular alternative to steroid injections, or it can be used after steroid injections to yield a better result.
Hypertrophic scars are similar, but are confined to the wound borders and usually regress over time. Hypertrophic scars are more common than keloids, and many people who think that they have keloids actually only have a tendency towards hypertrophic scarring. Your doctor can help make this distinction. The treatments for keloids and hypertrophic scars are similar, but hypertrophic scars usually have a better response to treatments.