Scarring and the Skin Healing Process

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

The skin is designed to heal wounds quickly to prevent blood loss and infection. Scars are crafted from a rapidly formed "collagen glue" that the body deposits into an damaged area for defense and strength. In ideal skin healing, wounded skin is rapidly closed, and then the healed area is slowly repaired to remove the residual 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 accelerate remodeling 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 reconstruct the skin area.

A second method is to use enzymes and activators of skin renewal fibroblasts to increase the body's normal reconstructing mechanisms 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 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 rose after the wound has healed but will become paler 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 cause itch or pain. Others develop scars that grow beyond the site of a wound, called keloid scars.

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

Keloids can appear after any type of injury to the skin, including scratches, insect bites, tattoos, injections or surgical procedures. Keloids 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 present a clinical 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 wounded site and often mature and flatten out over time. Both types produce larger quantities of collagen than normal scars, but typically the hypertrophic type shows less 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 changes 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 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 normal skin architecture. An example of an atrophic scar is striae distensae, also known as stretch marks.