Keloids and Hypertrophic Scars: Are They Two Different Sides of the Same Coin?

Abstract

Keloids and hypertrophic scars are different forms of excessive dermal fibrosis thought to be caused by regulation of cellularity increase and decrease during the wound-healing process in predisposed individuals. Differences between keloids and hypertrophic scars include distinct clinical features, histologic evidence, and cellular function in response to molecular events. Keloids and hypertrophic scars are the results of increased fibroblast density and extracellular matrix substances. Interactions between epidermal keratinocytes and dermal fibroblasts play an important role in regulating tissue homeostasis and processing scar formation. Keloids and hypertrophic scars are the two different stages of the same process that is based on separate clinical and histochemical entities. The aim of this review is to provide updated information regarding similarities and differences between keloids and hypertrophic scars as two different sides of the same coin. This article will also enable the dermatologist to better understand fundamental biology of the scarring.

Therapeutic potential of fibroblast growth factor-2 for hypertrophic scars: upregulation of MMP-1 and HGF expression

“…A large proportion of myofibroblasts expresses smooth muscle proteins such as a-smooth muscle actin (a-SMA). 4 HTS can be distinguished from keloids, the other major form of excessive scarring seen in humans. There is stronger evidence for genetic predisposition in keloid formation than in HTS.…”

“…9 a-SMAexpressing myofibroblasts are generally absent in keloids. 4 Apart from many differences, both HTS and keloid lesions likely represent aberrations in the fundamental processes of wound healing, causing excessive collagen production by fibroblast activity. 8,10 Most current research on HTS and keloids involves the evaluation of protein factors that control a complex series of wound healing processes in a highly systematic manner.…”

Lasers thermiques et cicatrisation cutanée

“…La cicatrisation cutanée est malheureusement un processus imprévisible. Si elle se déroule le plus souvent sans complication chez les sujets sains, elle est parfois source d'anomalies : cicatrisation excessive (botryomycome, chéloïdes), de mauvaise qualité (cicatrices rétractiles) ou déficitaire (plaies chroniques) [6][7][8]. Dans ces cas, la guérison est caractérisée par le dépôt de grandes quantités de matrice extracellulaire et par des altérations de la vascularisation locale et de la prolifération des cellules.…”

Long-Term Results of Intralesional Triamcinolone Acetonide Injections in Keloid Treatment

“…By definition, keloids are benign locally aggressive dermal fibro proliferative tumours that grow beyond the boundaries of the original wound [1,2]. The etiopathogenesis of keloid scarring has remained poorly understood to date [2][3][4][5]. In addition to pain and itching, keloids also cause functional and aesthetic impairment.…”