Keloid disease is a significant clinical problem for patients with skin of color.
Keloid scars are overgrowths of dense fibrous tissue which develop as a result of a cutaneous injury and invade the healthy tissue in the area surrounding the injury.
Hypertrophic scars are also overgrowths of fibrous tissue, but in contrast to keloids, they usually stay within the confines of the precipitating cutaneous injury.
Keloids differ from hypertrophic scars in their metabolic activity and collagen turnover.
Many theories have been advanced to explain the etiology of keloids, although none have been substantiated. However, it can be said that there is a familial tendency of keloid susceptibility. This hereditary tendency is more common in patients with skin of color.
Although keloids may be found anywhere on the body, they tend to have a regional predilection, occurring most often on the ears, anterior chest, upper back, and shoulders.
Although rare, keloids may develop on the genitalia, palms and soles, mucous membranes, tongue, and even cornea.
Synonyms for Keloids include:
Raised dermal scarring
Excessive scar tissue
Abnormal wound healing
Keloids are common, hyperproliferative, reticular, dermal lesions of unknown etiopathogenesis that often occur in genetically susceptible individuals. Keloid scars develop as a result of an overgrowth of scar tissue beyond the site of the original skin injury (no matter how minor) such as surgical incisions, traumatic wounds, vaccination sites, burns, chickenpox, acne, or even minor scratches. Keloids are more common in people with skin of color, such as African Americans.
Although keloids are clinically benign (not neoplastic), they can behave in an aggressive manner and are often psychologically and/or socially devastating for patients. Keloids represent an overgrowth of dense, fibrous tissue that develops as a result of even the most minor form of cutaneous injury. Hypertrophic scars usually stay within the confines of the precipitating injury, whereas keloids invade the surrounding noninjured normal skin. Additional clinical and histologic characteristics distinguish keloid scars from hypertrophic scars [Table 33-1]. However, the medical literature regarding hypertrophic scars and keloid scars is often confusing because many lesions that are keloid-like are mislabeled as hypertrophic scars or vice versa. Additionally, some patients have both kinds of scars caused by the same traumatic incident. Clinical studies often lump the two disorders together, thus leading to the dissemination of incorrect information, which is a practical concern when evaluating the therapeutic response.1,2
TABLE 33-1A comparison of keloids and hypertrophic scars ||Download (.pdf) TABLE 33-1 A comparison of keloids and hypertrophic scars
|Characteristics ||Keloids ||Hypertrophic scars |
|Stays in confines of injury ||No ||Yes |
|Precipitated by trauma ||Not always ||Yes |
|Area of occurrence ||Area of little motion ||Area of motion |
|Growth ||For extended period ||Regresses in time |
|Symptomatic ||Usually ||Usually |
|Response to treatment ||Poor ||Good |
|Sodium ||Normal ||Decreased |