Keloid scars are benign, but often disfiguring, tumour-like lesions that arise from the connective tissue elements of the skin. Classically, they are said to extend beyond the dimensions of the original wound or injury, grow relentlessly and are very refractory to treatment.
Wound healing progresses through three phases, inflammation, proliferation and remodelling. Keloids develop because of unchecked fibroblast growth and biosynthetic activity which starts during proliferation and progresses during maturation.
Keloids are distinct from hypertrophic scars. In the latter, the over-reactivity of the fibroblasts is ultimately checked and the scar hypertrophy remains within the boundaries of the original wound. There are thought to be other differences in their genetics, pathology, epidemiology and natural history (please see submenu).