Scarring and the Skin Repair Mechanisms

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 heal wounds rapidly to prevent blood loss and infection. Scars are manufactured from a quickly formed "collagen glue" that the body brings into an damaged area for defense and strength. In ideal skin healing, wounded skin is quickly closed, and then the healed area is slowly reconstructed to remove the residual 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 remodeling may continue in a skin area for up to ten years.

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

One way to accelerate 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.

An alternative procedure is to use enzymes and activators of skin renewal fibroblasts to increase the body's normal reconstructing processes and achieve 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 give moisture, tensile strength and elasticity to skin. Enzymes dissolve or "digest" damaged and dying cells.

Wound Healing

Scars are always needed to reconnect skin that has been damaged. Initially, they may be red or dark and rose 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 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 healed.

Keloid scars can appear after any type of injury to the skin, including scratches, tattoos, insect bites, injections or medical procedures. Keloid scars can appear on any part of the body, but most commonly occur on earlobes, over the breastbone 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 represent a therapeutic problem that must be addressed as these lesions can cause significant 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 sometimes are hard 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 secrete larger quantities of collagen than normal scars, but typically the hypertrophic type shows less collagen synthesis after about six months. Hypertrophic scars contain about twice as much glycosaminoglycans as normal scars, and this and enhanced synthetic and enzymatic activity result in marked alterations in the matrix which affects the mechanical properties of the scars, including decreased 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 alert their doctor or surgeon if they are going to need injections or to have any form of surgery.

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