Keloid is a type of scar tissue that appears around a wound after it has closed and healed. This is the main difference between it and a hypertrophic scar. While the hypertrophic scar remains only in the area of the original wound, the keloid one grows outside its border and covers a larger area.
The current name of this scar comes from the Greek word "chele", which led to the initial name "chéloïde". The Greek word designates the claw of a crab and it is related to the scar's tendency to expand sideways.
For some reason, keloids are mostly found on people with dark skin, who have a 15 times higher risk to develop one than white-skinned people. African, Asian and Hispanic people are the most affected races. Otherwise, the condition affects both males and females but youngsters and elders have a lower chance to develop it. Keloids can still affect people with white skin, even if this is uncommon. Vulnerability to keloids also seem to be transmitted, since they tend to affect people from the same family. However, the exact genes that cause it have not been identified yet.
Scientists don't know exactly why keloids develop. They seem to be connected with infections, since infected wounds have a higher chance to become keloids. Various types of wound can cause it: surgery, burns, acne, boils, lacerations or body piercings. The fibroblast cells in the skin are in charge to produce collagen. Collagen is needed for skin elasticity and healing of the wounds. Keloids occur after a problem with these cells. It is not clear if the cells themselves are faulty, or if the problem is caused by chemicals or hormones that control them. Other causes might be genetic issues, immune-related problems or a hormonal imbalance. The genetic link is suspected because the condition appears to be transmitted in the family, through the genes found in every cell of the body.
Keloid has a delayed start. It usually starts to grow about three months after a wound is caused but the period can be longer, even reaching one year. It all begins at the borders of the initial wound, with a scar tissue with a rubber-like texture. Sometimes this tissue is sensitive when touched, or it can cause itching, burning or pain. In rare situations, the keloid can even appear without any obvious wound. Initially, the scar is red. In time, its color changes to either a pale red or brown. The most vulnerable areas of the body to keloid scars are the breasts, shoulders, cheeks or earlobes. If the scar develops over an articulation, its movement might be affected.
The keloid grows slowly for some weeks or a few months. Sometimes, the slow pace can be replaced by a fast expansion that lasts for months. At some point, the scar stops growing and remains at its current size. Rarely, the surface of the keloid scar can reduce in time.
Keloid scars look like an area of skin that can be red, pink or the same color as the rest of the skin. Usually, keloids have a raised profile and look like lumps. The distinctive trait of keloids is that their size continues to expand long after the initial wound has healed completely. The area can be itchy in some cases.
Besides this itchiness, the scars are not a serious health problem. Sometimes the skin can be sensitive when touched or it can become irritated if repeatedly rubbed by clothes. Keloids become a real problem when they expand over large areas of skin. Since the scar tissue is a lot thicker and less elastic than normal skin, this can impair movement and agility.
While keloids are rarely a significant health problem, they usually are an aesthetic one. Keloids located on the face, earlobes or other visible locations can be embarrassing, especially if their size is large. A common problem with scars is when the rest of the skin is tanned, which makes them more obvious than normal. One way around this problem is to keep the scar covered and protected from the sun, in order to preserve its initial color.
No definitive treatment for keloids exists but combining some of the available ones might give good results. At the moment, none of them can remove a keloid on its own. For best results, the treatment must be started as soon as possible after the scar emerges for the first time. There are a number of options available, more or less effective.
The scar can be eliminated by classic surgical means but this is rarely a good idea. The procedure is complicated and must be done with great care. Sometimes, it doesn't solve the problem and actually causes a keloid scar larger than the initial one. About 45% of patients develop a new keloid after conventional surgery, although the risk can be decreased in combination with other forms of treatment.
Studies have identified a painless treatment with no side effects that can sometimes make keloid scars shrink. It involves dressing the wound with a moist layer of silicone gel. It should be done over a long period of time, in order to notice any effects.
Corticosteroid injections, repeated every four or six weeks, can reduce the irritation around keloids and sometimes their size as well. The corticosteroid compound used most often is triamcinolone acetonide. Injections can be painful, so this is not an easy treatment to administrate.
Cryosurgery is a modern treatment option, based on freezing the skin with liquid nitrogen. It is not often used because it has a significant side effect: it makes the color of the skin lighter in the entire area. It must be repeated at intervals of 20 or 30 days.
Radiation therapy can be effective while a wound is still healing. It is sometimes used after surgery to prevent the development of scars but few people choose this form of treatment, since it is known to increase the risk of cancer in the area.
Laser therapy is no more than a modern replacement for conventional surgery, with the same end result. The risk of developing a new or larger keloid scar seems to be similar to normal surgery.