Keloid disorder has a fascinating and very diverse presentation. This disorder can present itself as a single spot on the skin of the affected individual, or it can involve several areas of the skin. In some cases, presentation is limited to one or few small lesions of the skin; either round or linear; in other cases, keloids can appear as large nodules, conglomerate of nodules, or appear as very large patches.
Such a diverse presentation is most likely associated with a complex genetics, involving more than one gene. Unfortunately, we have no knowledge as to how the vast and varied presentations of this disorder can correlate with any particular set of genetic abnormalities. This has been topic of several studies, none of which have provided any solid evidence for any particular genetic abnormality that can explain development of this condition.
Keloids develop in genetically predisposed individuals as a consequence of injury to the skin that acts as a triggering factor in formation of keloid lesions. These triggering factors range from minor inflammatory skin reactions of the skin to acne, chicken pox, vaccination; or from body piercing, surgical wounds, burns, etc. Although reported in individuals from almost all ethnic backgrounds, the disease is more common among two distinct and genetically distant populations; Africans / African Americans and Asians. The only groups of individuals who may be spared from developing keloids are albinos, making the case for a relationship between melanin (skin pigment) production and susceptibility to keloid formation, at least among dark-skinned individuals. Most keloid patients, especially Africans and African Americans have a positive family history of keloids. Development of keloids among twins also lends credibility to existence of a genetic susceptibility to develop keloids.
The variable presentation of the disorder is perhaps due to its complex and multi-gene inheritance, with certain individuals perhaps having only one mutations or one genetic abnormality who develop only one or few keloid lesions, to those who have inherited two or more genetic mutations, whereby the disorder appears in its most severe form.
Much more research needs to be done to determine the genetic cause of keloid disorder. Lack of progress in keloid disorder is in part due to lack of a lobbying group for this condition. Although quite common, keloid has not captured the interest of research community. This needs to change.