The relationship between skin stretching/contraction and pathologic scarring: The important role of mechanical forces in keloid generation

TLDR

Keloids preferentially develop on highly mobile, high‑tension sites, and mechanotransduction research aims to reduce skin tension around wounds to prevent keloids and hypertrophic scars. The study aimed to assess whether body areas experiencing large strain during normal activities are associated with higher keloid rates after wounding. Eight Japanese volunteers had skin stretching/contraction rates measured at nine body sites by marking points during typical movements, and the distribution of 1,500 keloids in 483 patients was mapped. Keloids were rare on low‑stretch sites such as the parietal region and anterior lower leg, common on highly stretched areas like the suprapubic region, with the anterior chest (48.9%) and scapular regions (26.9%) being the most frequent sites, and none on the scalp or anterior lower leg, underscoring mechanical force as a key trigger.

Abstract

Keloids tend to occur on highly mobile sites with high tension. This study was designed to determine whether body surface areas exposed to large strain during normal activities correlate with areas that show high rates of keloid generation after wounding. Eight adult Japanese volunteers were enrolled to study the skin stretching/contraction rates of nine different body sites. Skin stretching/contraction was measured by marking eight points on each region and measuring the change in location of the marked points after typical movements. The distribution of 1,500 keloids on 483 Japanese patients was mapped. The parietal region and anterior lower leg were associated with the least stretching/contraction, while the suprapubic region had the highest stretching/contraction rate. With regard to keloid distribution, there were 733 on the anterior chest region (48.9%) and 403 on the scapular regions (26.9%). No keloids were reported on the scalp or anterior lower leg. Because these sites are rarely subjected to skin stretching/contraction, it appears that mechanical force is an important trigger that drives keloid generation even in patients who are genetically predisposed to keloids. Thus, mechanotransduction studies are useful for developing clinical approaches that reduce the skin tension around wounds or scars for the prevention and treatment of not only keloids but also hypertrophic scars.