Unfortunately, scars are a fact of life. Their main purpose is to reconnect skin that has been injured. At first, 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 develop raised scars that are red and thick and may be itchy or painful. Others form scars that grow beyond the site of a wound, called keloid scars.

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

Keloid scars can result from any kind 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 usually occur over the breastbone, on earlobes and on shoulders.

Keloids are fibrotic tumors characterized by a mass of atypical fibroblasts with high accumulation of extracellular matrix components, especially fibronectin, elastin, collagen, and proteoglycans. Histologically, keloids have mostly acellular centers and thick, abundant collagen bundles that create nodules in the deep dermal section of the lesion. Keloids present a clinical challenge that must be addressed as these lesions can produce significant pain, pruritus (itch) and physical disfigurement, may not improve in appearance over time, and can even limit mobility if located 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 differentiate from keloid scars histologically and biochemically because both types accumulate larger quantities of collagen than normal scars. Both can be caused|the result of surgery, accidents and even acne.

Hypertrophic scars, however, will often show declining collagen production after about six months. Hypertrophic scars have about twice as much glycosaminoglycans as normal scars, and this and increased synthetic and enzymatic reactions result in significant changes in the matrix which affects the mechanical capabilities 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 reduced elasticity of the skin due to an alteration 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.