Keloid, also known as keloid disorder and keloidal scar,
is the formation of a type of scar which, depending on its maturity, is composed mainly of either type III (early) or type I (late) collagen. It is a result of an overgrowth of granulation tissue (collagen type 3) at the site of a healed skin injury which is then slowly replaced by collagen type 1. Keloids are firm, rubbery lesions or shiny, fibrous nodules, and can vary from pink to the color of the persons skin or red to dark brown in color. A keloid scar is benign and not contagious, but sometimes accompanied by severe itchiness, pain, and changes in texture. In severe cases, it can affect movement of skin. Worldwide, men and women of African, Asian, Hispanic and European descent can develop these raised scars. In the United States keloid scars are seen 15 times more frequently in people of sub-Saharan African descent than in people of European descent. There is a higher tendency to develop a keloid among those with a family history of keloids and people between the ages of 10 and 30 years. Keloids should not be confused with hypertrophic scars, which are raised scars that do not grow beyond the boundaries of the original wound. Signs and symptoms
Keloids expand in claw-like growths over normal skin. They have the capability to hurt with a needle-like pain or to itch, the degree of sensation varying from person to person.Keloids form within scar tissue.
Studies have shown that those with darker complexions are at a higher risk of keloid scarring as a result of skin trauma. They occur in 15–20% of individuals with sub-Saharan African, Asian or Latino ancestry, significantly less in those of a Caucasian background. Although it was previously believed that people with albinism did not get keloids, a recent report described the incidence of keloids in Africans with albinism. Keloids tend to have a genetic component, which means one is more likely to have keloids if one or both of their parents has them. However, no single gene has yet been identified which is a causing factor in keloid scarring but several susceptibility loci have been discovered, most notably in Chromosome 15. Genetics
People who have ancestry from Sub-Saharan Africa, Asia, or Latin America are more likely to develop a keloid. Among ethnic Chinese in Asia, the keloid is the most common skin condition. In the United States, keloids are more common in African Americans and Hispanic Americans than European Americans. Those who have a family history of keloids are also susceptible since about 1/3 of people who get keloids have a first-degree blood relative (mother, father, sister, brother, or child) who also gets keloids. This family trait is most common in people of African and/or Asian descent. Development of keloids among twins also lends credibility to existence of a genetic susceptibility to develop keloids. Marneros et al. (1) reported four sets of identical twins with keloids; Ramakrishnan et al.