True incidence and prevalence of keloid in United States is not known. Indeed, there has never been a population study to assess the epidemiology of this disorder. In his 2001 publication, Marneros  stated that “reported incidence of keloids in the general population ranges from a high of 16% among the adults in Zaire to a low of % in England,” quoting from Bloom’s 1956 publication on heredity of keloids.  We do however know, from clinical observations that the disorder is more common among Africans, African Americans and Asians with unreliable and very wide estimated prevalence rates ranging from -16%.   Thorough and scientific population and epidemiology studies of this disorder are desperately needed.
Silicone gel sheets and silicone occlusive dressings have been used with varied success in the treatment of keloids. The sheets can be worn for as long as 24 h/d for up to 1 year, with care to avoid contact dermatitis and skin breakdown. The silicone does not appear to enter the skin; therefore, the antikeloid effects appear to be secondary to both occlusion and hydration. Studies have demonstrated that silicone gel increases the temperature of the scar, possibly increasing collagenase activity. Increased pressure, hydration of the stratum corneum, and direct pressure on the wound also may be modes of action. In some studies, the response rate has been as high as 79%, showing substantial reduction in erythema, scar elevation, and pruritus. [ 9 ] However, complete resolution has not been noted.
Meshkinpour et al (2005) examined the safety and effectiveness of the ThermaCool TC radiofrequency system for treatment of hypertrophic and keloid scars and assessed treatment associated collagen changes. Six subjects with hypertrophic and 4 with keloid scars were treated with the ThermaCool device: 1/3 of the scar received no treatment (control), 1/3 received one treatment and 1/3 received 2 treatments (4-week interval). Scars were graded before and then 12 and 24 weeks after treatment on symptoms, pigmentation, vascularity, pliability, and height. Biopsies were taken from 4 subjects with hypertrophic scars and evaluated with hematoxylin and eosin (H & E) staining, multi-photon microscopy, and pro-collagen I and III immunohistochemistry. No adverse treatment effects occurred. Clinical and H & E evaluation revealed no significant differences between control and treatment sites. Differences in collagen morphology were detected in some subjects. Increased collagen production (type III > type I) was observed, appeared to peak between 6 and 10 weeks post-treatment and had not returned to baseline even after 12 weeks. The authors concluded that use of the thermage radiofrequency device on hypertrophic scars resulted in collagen fibril morphology and production changes. ThermaCool alone did not achieve clinical hypertrophic scar or keloid improvement. They noted that the collagen effects of this device should be studied further to optimize its therapeutic potential for all indications.