Scarring and the Skin Healing 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 quickly to avoid blood loss and infection. Scars are created from a quickly formed "collagen glue" that the body deposits into an damaged area for protection and strength. In ideal skin repairing, damaged skin is quickly 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 removed 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 removed from damaged skin areas. But as we reach adulthood, this rate diminishes and small scars may remain for years.

One way to quicken repair is to provoke 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 normal healing 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 needed to reconnect skin that has been damaged. 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 form raised scars that are red and thick and may cause itch or pain. Others develop scars that extend beyond the site of an injury, called keloid scars.

Keloid scars are actually thick, puckered, itchy clusters of scar tissue that grow beyond the edges of a wound or incision and rarely regress. They appear when the body keeps producing tough, fibrous protein (known as collagen) after a wound has been repaired.

Keloids can result from any type of injury to the skin, including scratches, tattoos, injections, insect bites or medical procedures. Keloids can appear anywhere on 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 excessive 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 problem that must be addressed as these lesions can cause great pain, pruritus (itch) and physical disfigurement, may not improve its appearance over time, and can even affect 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 remain confined to the injury site and often mature and flatten out over time. Both types secrete larger amounts of collagen than normal scars, but typically the hypertrophic type exhibits declining collagen synthesis after about six months. Hypertrophic scars contain nearly twice as much glycosaminoglycans as normal scars, and this and enhanced synthetic and enzymatic reactions result in important 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 who have developed one keloid scar are likely to be prone to another one in the future and should alert their doctor or surgeon if they are going to need injections or to have any kind 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.