We are all concerned about scars. We may have an injury, a surgery, bad acne, an infection or abscess, which leads to a wound on the skin, which needs to heal. We worry: will it leave a scar? How bad will the scar be? What determines whether or not the scar will be noticeable? What is a scar anyway?
The body is quite remarkable in its ability to heal a wound. If a wound to the skin is very superficial, the new cells that replace the old ones may be an exact match of texture and color to the original tissues. The result of the ensuing healing may be undetectable. If the wound is deeper, more repairs must take place and a scar is formed.
A scar is a collection of fibrous collagen protein created by cells that live in the skin, called fibroblasts. The new scar tissue varies from the original tissues in that the new bundles of collagen are linearly arranged, and often denser, less elastic than the original. If the wound is large enough, the new “skin” will lack the sweat glands, nerves and other structures and cells found in normal skin. The result is an area of skin, which differs in texture and color, from the original: a scar.
There are a few variations of scar formation. Overproduction of collagen may lead to a hypertrophic scar, which appears as a dark red, thickened ropy growth. If the overgrowth is extreme, the scar may be very large and bulbous. This is known as a keloid. Hypertrophic scars may occur in areas of high tension on the edges of a wound. Some areas of the body are more prone to hypertrophic scars; notably, the chest, shoulders, backs of the hands, and angle of the jaw. The tendency to form keloids is likely genetically determined. Even the most minor wound may result in a keloid in a predisposed individual.
Loss of the underlying tissues may result in an atrophic scar. It may appear sunken or pitted. Acne and chicken pox scars are often atrophic.
A secondary undesirable wound healing phenomenon is discoloration. In more olive and darker skin-types, dark pigment may form in and around the wound, making it more noticeable. In more fair-skinned individuals, a scar may turn white over time.
Most wounds will heal flat. There is a natural remodeling process over time, which generally leads to the improved appearance of scars. Often, there is initial redness, which typically resolves over time. However, in certain situations, particularly in individuals prone to form hypertrophic scars or keloids, early intervention may be desirable. Most hypertrophic and keloid scars will start to form within 6 to 8 weeks after the initial wound. This is an ideal time to use intralesional cortisone or a pulsed dye laser. Cortisone can be injected into a thickened scar of any age. Cortisone helps flatten the scar. It does not help the color. More than one treatment may be needed. A pulsed dye laser will improve the color of a dark red scar and improve the texture of a thickened scar of any age.
Re-excision and surgical repair of a scar may be advantageous in some situations.
Acne and chicken pox scars may be improved by use of more aggressive ablative techniques, such as dermabrasion, or CO2 laser (full or fractionated). However, individuals with olive and darker skin are usually not candidates, as they are at high risk for further scarring and discoloration.
There is little evidence to support the use of onion extract (Mederma) or Vitamin E. The evidence supporting the use of silicone sheets is weak.
Protection from the sun for at least 6 weeks is advised for a new wound and treatment of scars.