When the skin is injured, fibrous tissue (scar tissue) forms over the wound to repair and protect the injury. In some cases, scar tissue grows excessively, forming smooth, hard growths called keloids. Keloids are firm, rubber-like lesions or shiny, fibrous nodules, and can vary from pink to the colour of the patient’s skin, or red to dark brown in colour. A keloid scar is benign and not contagious, but is sometimes accompanied by severe itchiness, pain, and changes in texture. In severe cases, it can affect movement of the skin. Keloid scars are seen 15 times more frequently in highly pigmented ethnic groups than in Caucasians.
A hypertrophic scar is a cutaneous condition characterized by deposits of excessive amounts of collagen, which gives rise to a raised scar, but not to the degree observed with keloids. Most oftenly, like keloids, they form at the sites of pimples, body piercings, cuts and burns. They often contain nerves and blood vessels. They generally develop after thermal or traumatic injury.