Scars are the result of the healing process. Collagen forms beneath the skin as a part of the process of wound healing. Scars are formed from wounds, burns, surgeries, accidents, stretch marks and skin diseases. Scars heal differently based upon the type of wound and individual factors that determine the size and look of the scar. Scars heal in three phases: the inflammatory stage, the proliferative stage and the remodeling stage.
The inflammatory stage is the first stage. It lasts only a few days. At this stage, the wound is red and inflamed. Bleeding stops and antibodies rush to the site of the wound to fight infection. As the body starts to heal, it produces new cells and healing tissue. The increased blood flow is what causes the discoloration, according to the Free Medical Dictionary. Scabbing over of the wound is also part of the inflammatory stage. The scab serves as a protective covering on the wound while it heals.
The proliferative stage lasts about three to four weeks. Skin-forming cells, called fibroblasts, proliferate at the site of the wound. These fibroblasts produce collagen. Collagen continues to form for up to two weeks, pulling the edges of the wound together. Tiny blood vessels and capillaries form to help heal the wound. The growth of collagen causes the wound to become thicker and redder in appearance.
An over-active healing process can cause extra production of collagen that builds up on the wound causing a raised, or keloid scar. Keloids can cause itchiness, redness, unusual sensations and even pain, according to the American Osteopathic College of Dermatology. Darker skinned people are more prone to keloids, but lighter skinned people can develop keloids also.
In the remodeling stage, scars start to fade and thin out. This stage continues for a few weeks to a few years, according to the Cleft Palate Foundation. Over time, some scars fade to a thin white line and are barely noticeable.
Genetics play an important role in how a scar will heal. Some scars produce lighter, flatter scars, while others produce darker, thicker scars. Illnesses can slow the healing process and change how a wound heals. Certain vitamins help the body in the healing process, such as vitamin C and zinc. Other factors that affect how a scar will look include whether you smoke, skin quality and blood supply to the area.