Scarring and the Skin Repair Process

The removal or fading of scars, lesions, and stretch marks from the skin depends on a process called "skin remodeling".

The skin is meant to repair wounds rapidly to prevent blood loss and infections. Scars are manufactured from a rapidly formed "collagen glue" that the body deposits into an damaged area for protection and strength. In ideal skin repairing, damaged skin is rapidly closed, and then the healed area is slowly repaired to remove the remaining collagen scars and blend the skin area into nearby skin.

Scar collagen is eliminated and replaced with a mix of skin cells and invisible collagen fibers. This work may continue in a skin area for up to ten years.

In children, the remodeling rate is high and scars are often rapidly eliminated from damaged skin areas. But as we become adults, this rate diminishes and small scars may stay there for years.

One way to quicken remodeling is to induce a small amount of controlled skin damage with a needle, laser, acid, or other means, and then let the body repair processes rebuild the skin area.

A second procedure is to use enzymes and fibroblast proliferators to increase the body's natural rebuilding mechanisms and obtain even better final results. Fibroblasts are the cells in the basal membrane of the skin and they are the precursors of all the structural elements of healthy skin, including those that provide moisture, tensile strength and elasticity to skin. Enzymes dissolve or "digest" damaged and dying cells.

Wound Repair Process

Scars are always formed to reconnect skin that has been injured. Initially, they may be red or dark and pink after the wound has been healed but will become softer and flatter naturally over time, resulting in a flat, pale scar.

For reasons that are still waiting to be fully understood, some people suffer from raised scars that are red and thick and may be itchy or painful. Others develop scars that extend beyond the site of an injury, called keloid scars.

Keloid scars are actually thick, itchy, puckered scars that grow beyond the edges of an injury or incision and rarely regress. They appear when the body continues to produce tough, fibrous protein (known as collagen) after a wound has healed.

Keloids can result from any type of injury to the skin, including scratches, injections, tattoos, insect bites or surgical procedures. Keloids can appear on any part of the body, but most commonly occur over the breastbone, on earlobes and on shoulders.

Keloids are fibrotic tumors characterized by a collection of atypical fibroblasts with high deposition of extracellular matrix components, especially collagen, fibronectin, elastin, and proteoglycans. Histologically, keloids contain relatively acellular centers and thick, abundant collagen bundles that form nodules in the deep dermal portion of the lesion. Keloids present a therapeutic challenge that must be addressed as these lesions can cause great pain, pruritus (itch) and physical disfigurement, may not improve in appearance over time, and can even limit mobility if located over a joint.

Hypertrophic scars use to be difficult to distinguish from keloid scars histologically and biochemically, but unlike keloids, hypertropic scars are confined to the injury site and often mature and flatten out over time. Both types produce larger quantities of collagen than normal scars, but often the hypertrophic type shows declining collagen synthesis after about 24 weeks. Hypertrophic scars contain about twice as much glycosaminoglycans as normal scars, and this and enhanced synthetic and enzymatic reactions result in significant alterations in the matrix which affects the mechanical properties of the scars, including less extensibility that makes them feel firm.

As with hypertrophic scarring, people having one keloid scar are likely to be prone to another one in the future and should speak with their doctor or surgeon if they are likely to need injections or to have any form of surgery.

Atrophic scars use to cause a thinning and diminished elasticity of the skin due to a loss of normal skin architecture. An example of an atrophic scar is striae distensae, also called stretch marks.