What is a keloid scar?
Keloids can be considered to be “scars that don’t know when to stop.” A keloid, sometimes referred to as a keloid scar, is a tough heaped-up scar that rises quite abruptly above the rest of the skin. It usually has a smooth top and a pink or purple color. Keloids are irregularly shaped and tend to enlarge progressively. Unlike scars, keloids do not regress over time.
What is the cause of keloids?
Doctors do not understand exactly why keloids form. Alterations in the cellular signals that control proliferation and inflammation may be related to the process of keloid formation, but these changes have not yet been characterized sufficiently to explain this defect in wound healing.
What are keloid risk factors?
Individuals with darkly pigmented skin are 15 times more likely to develop keloids, with those of African, Hispanic, and Asian ethnicity are at greatest risk. Keloids are equally common in women and men. Keloids are less common in children and the elderly. Although people with darker skin are more likely to develop them, keloids can occur in people of all skin types. In some cases, the tendency to form keloids seems to run in families. Studies have not as yet delineated the exact genes responsible for this predisposition.
What is the difference between a keloid, hypertrophic scar, and a dermatofibroma?
After the skin is injured, the healing process usually leaves a flat scar. Sometimes the scar is hypertrophic, or thickened, but confined to the margin of the original wound. Hypertrophic scars tend to be redder and often regress spontaneously (a process which can take one year or more). Treatment, such as injections of cortisone (steroids), can speed this process.
A dermatofibroma is a small, benign, pigmented, very firm bump in the skin that does not cause other symptoms. It is most often found on the legs. Dermatofibromas are almost never larger than ½ to ¾ of an inch and remain unchanged over many years.
Keloids, by contrast, may start sometime after a cutaneous injury and extend beyond the wound site. This tendency to migrate into surrounding areas that weren’t injured originally distinguishes keloids from hypertrophic scars. Keloids typically appear following surgery or injury, but they can also as a result of some minor inflammation, such as an acne pimple on the chest (even one that wasn’t scratched or otherwise irritated). Other minor injuries that can trigger keloids are burns and cosmetic piercings.
We use a combination of injections and lasers to treat keloid and scars. The basic concept is to shrink the number of very small blood vessels that feed these hyperactive scar cells and to inject them with medications that reduce their cellular activity.