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 wound has been healed 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 develop raised scars that are red and thick and may be itchy or painful. Others develop scars that grow beyond the site of an injury, called keloid scars.

Keloid scars are basically engrossed, itchy, puckered scars that grow beyond the limits of an injury or incision and rarely regress. They occur when the body keeps producing tough, fibrous protein (called collagen) after an injury has healed.

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

Keloids are fibrous tumors characterized by a mass of aberrant fibroblasts with high accumulation of extracellular matrix components, especially fibronectin, collagen, elastin, and proteoglycans. Histologically, keloids contain relatively acellular centers and engrossed, abundant collagen accumulations that create nodules in the deep dermal portion of the lesion. Keloids present a clinical challenge that must be attended as these lesions can cause 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 wounded site and usally flatten out over time. Hypertrophic scars can be difficult to distinguish from keloid scars microscopically and biochemically because both types produce larger amounts of collagen than normal scars. Both can be caused|the result of surgery, accidents and even acne.

Hypertrophic scars, however, will often exhibit declining collagen production after about six months. Hypertrophic scars contain about twice as much glycosaminoglycans as normal scars, and this and enhanced synthetic and enzymatic reactions result in 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 scars in the future and must speak with their doctor or surgeon 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 called stretch marks. This type of scar can also be produced by acne lesions.