Keloid, also known as keloid disorder and keloidal scar, is the formation of a type of scar which, depending on its maturity, is composed mainly of either type III (early) or type I (late) collagen. It is a result of an overgrowth of granulation tissue (collagen type 3) at the site of a healed skin injury which is then slowly replaced by collagen type 1.
Most keloids respond to injection of a steroid called triamcinolone into the scar. Injections are given every 2-6 weeks until improvement is seen. Occasionally, injections can cause a network of surface veins to develop (telangiectasias), or lightening or thinning of the surrounding skin.