Unfortunately, scars are a fact of life. Their main goal is to reconstruct skin that has been damaged. Initially, they may be red or dark and rose after the injury has been cured but will become paler and flatter naturally over time, resulting in a flat, pale scar.

For reasons that are still not completely understood, some persons form raised scars that are red and thick and may be itchy or painful. Others develop scars that grow beyond the site of a wound, called keloid scars.

Keloid scars are basically thick, itchy, puckered scars that grow beyond the limits of a wound or incision and rarely regress. They occur when the body keeps producing tough, fibrous protein (known as collagen) after a wound has healed.

Keloid scars can result from any type of damage to the skin, including scratches, tattoos, insect bites, injections or medical procedures, etc. Keloid scars can show anywhere on the body, but most commonly occur over the breastbone, on earlobes and on shoulders.

Keloids are fibrotic tumors characterized by a mass of aberrant fibroblasts with high deposition of extracellular matrix components, especially fibronectin, elastin, collagen, and proteoglycans. Histologically, keloids have mostly acellular centers and thick, abundant collagen accumulations that create nodules in the deep dermal portion of the lesion. Keloids present a clinical challenge that must be addressed as these lesions can produce great pain, pruritus (itch) and physical disfigurement, may not improve in appearance over time, and can even restrict mobility if formed over a joint.

Unlike keloids, hypertropic scars are limited to the injured site and usally flatten out over time. Hypertrophic scars can be difficult to distinguish from keloid scars microscopically and biochemically because both kinds produce larger amounts of collagen than normal scars. Both can be caused|the result of surgery, accidents and even acne.

Hypertrophic scars, however, will usually exhibit declining collagen production after about six months. Hypertrophic scars have about twice as much glycosaminoglycans as normal scars, and this and enhanced artificial and enzymatic reactions produce significant changes in the matrix which affects the mechanical properties of the scars, including decreased extensibility that makes them feel firm.

As with hypertrophic scars, persons having one keloid scar are likely to be prone to this condition in the future and must speak with their doctor or specialist if they are likely to need injections or to have any kind of surgery.

Atrophic scars are characterized by a thinning and diminished elasticity of the skin due to a loss of regular skin architecture. An example of an atrophic scar is striae distensae, also known as stretch marks. This type of scar can also be produced by acne lesions.