Keloid scars are defined as abnormal scars that grow beyond the boundary of the original site of a skin injury. The scar is a raised and ill-defined growth of skin in the area of damaged skin. Although a keloid scar can form on anyone, some ethnic groups are at a greater risk of developing them: African Americans and Hispanics are 16% more susceptible, for example, and keloid scars are seen 15 times more frequently in highly-pigmented ethnic groups than in Caucasians.
Parts of the body susceptible to keloids
Some areas of the body do seem more susceptible to keloid scars, including the deltoid region of the upper arm, the upper back, and the sternum. The earlobes and the back of the neck are also common sites.
Causes of keloid scars
It is not fully understood why or how keloid scars form. Skin trauma appears to be the most common cause, although scars can also form for no apparent reason. Skin and/or muscle tension seems to contribute to keloid formation, as is evidenced by the most common sites of their formation (the upper arm and back). But if that was the full story, you would expect that other sites, such as the palm of the hand or the soles of the feet, to be just as vulnerable; however, this is not the case. Infection at a wound site, repeated trauma to the same area, skin tension or a foreign body in a wound can also be factors.
There does appear to be a genetic component to keloid scarring: it is known that if someone in your family has keloids, then you are at increased risk.
Other theories for the causes of keloid scarring include: a deficiency or an excess in melanocyte hormone (MSH); decreased percentages of mature collagen and increased soluble collagen; or that very small blood vessels get blocked, and the resulting lack of oxygen contributes to keloid formation.
While the lack of a clear cut theory does demonstrate the lack of understanding of the condition, some work is being done to find the cause. Determining the exact cause will hopefully mean better preventative medicine and more effective treatments in the future, but there are many problems with adequate follow up of people with the condition, lack of a clear cut-off from treatment, and too few studies in general — all hampering the search for a cure.
Can you prevent keloid scars?
The fact is that there may be little you can do if you are unfortunate enough to have the sort of skin that reacts by forming keloid scarring. You can assist the healing process by keeping any wounds clean, and if you know you are susceptible because of previous experience or a family connection, then you can avoid taking extra risks. Do not get piercings or tattoos, and make sure you tell your doctor if you are going to have surgery.
There is a high rate of recurrence: up to 50%. Some doctors say that all highly pigmented people should avoid tattoos and piercings to be on the safe side.