Insights into the Pathophysiology of Hypertrophic Scars and Keloids: How Do They Differ?

Abstract

After completing this continuing education activity, you should be able to: ABSTRACT: Hypertrophic scars and keloids are firm, raised, erythematous plaques or nodules that manifest when the cicatrix fails to properly heal. They result from pathologic wound healing and often cause pain and decreased quality of life. The appearance of such cosmetically unappealing scars affects the confidence and self-esteem of many patients. These scars can also cause dysfunction by interfering with flexion and extension across joints. Both possess some unique and distinct histochemical and physiologic characteristics that set them apart morphologically and at the molecular level. While these entities have been the focus of research for many years, differentiating between them remains challenging for clinicians.This article reviews the clinical presentation of aberrant scars and illustrates how they can be differentiated. It outlines their pathophysiology and emphasizes the unique molecular mechanisms underlying each disorder. It also examines how altered expression levels and the distribution of several factors may contribute to their unique clinical characteristics and presentation. Further research is needed to elucidate optimal treatments and preventive measures for these types of aberrant scarring.

Botulinum toxin type A for the treatment and prevention of hypertrophic scars and keloids: Updated review

“…Wound healing involves a complicated, concurrent process that occur mainly in three phrases, an inflammation phase, a granulation tissue formation phase, and a matrix formation or remodeling phase . When there are any alterations in these wound healing phases, it can dispose an individual to pathological scars . These pathological scars include hypertrophic scars and keloids .…”

“…These pathological scars can also occur as a result of cutaneous irritation that would lead to prolonged inflammation, such as insect bite, vaccination, and some skin infections such as herpes zoster . The prevalence of hypertrophic scars and keloids is equal to both men and women, but keloids are more prevalent in people of color (Asians and Blacks) . In some cases, one of the two could be mistaken for the other.…”

“…In some cases, one of the two could be mistaken for the other. Hypertrophic scars are usually raised, but seldom elevated 4 mm above the skin, reddish or pinkish in color, hard, pruritic, and do not extend beyond the general margins of the wound . The pathogenesis of hypertrophic scars has not been fully elucidated.…”

“…However, some of the factors associated with the formation of hypertrophic scars and keloids include inflammation, neural factors, cytokines, and tension. The secretion of interleukin 12 (IL‐12) and interferon gamma have been linked to skin fibrosis which results in the development of both hypertrophic scars and keloids, whereas the secretion of cytokines (IL‐4, IL‐5, IL‐10, and IL‐13) have been linked to the development of keloids . Keloids behave like benign tumors, they grow beyond wound margins and they can form spontaneously or as a result of a predisposing genetic disorders such as Rubinstein‐Taybi syndrome .…”

“…The treatment of both hypertrophic scars and keloids still remain a challenge due to their unclear etiology. Current treatments include surgical and nonsurgical methods such as compression, silicone sheet, cryotherapy, laser, intralesional steroid injections, intralesional 5‐FU injections, and intralesional Botulinum Toxin A (BoNT‐A) injections . Intralesional BoNT‐A injection is now one of the most promising methods for the prevention and treatment of hypertrophic scars and keloids.…”