A scar results from the biologic process of wound repair in the skin and other tissues of the body. Thus, scarring is a natural part of the healing process. With the exception of very minor lesions, every wound (e.g. after accident, disease, or surgery) results in some degree of scarring.
Scar tissue is not identical to the tissue which it replaces and is usually of inferior functional quality. For example, scars in the skin are less resistant to ultraviolet radiation, and sweat glands and hair follicles do not grow back within scar tissue, myocardial infarction causes scar formation in the heart muscle which leads to loss of muscular power and possibly heart failure. However, there are some tissues (e.g. bone) which can heal without any structural or functional deterioration.
Scars of the skin
A scar is a natural part of the healing process. Skin scars occur when the deep, thick layer of skin (the dermis) is damaged.
To mend the damage, the body has to lay down new collagen fibres (a naturally occurring protein which is produced by the body).
This process results in a scar. Because the body cannot re-build the tissue exactly as it was, the new scar tissue will have a different texture and quality to the surrounding normal tissue. An injury does not become a scar until the wound has completely healed.
Most skin scars are of the flat and pale variety, which leave a trace of the original injury which caused them.
Sometimes the body can over-produce collagen, which results in a scar which is raised above the surrounding skin, these are known as either Hypertrophic scars or Keloid scars. Hypertrophic scars take the form of a red raised lump on the skin, but do not grow beyond the boundaries of the original wound, and they often improve in appearance after a few years. Keloid scars are a more serious form of scarring, because they can carry on growing indefinitely into a large, tumorous (although benign) growth. These are caused when the body doesn't know when to stop producing collagen.
Both hypertrophic and keloid scars are more common on younger and darker skinned people. They can occur on anyone, but some people have a genetic succeptibility to these types of scarring. They can be caused by surgery, an accident, or sometimes by acne. In some people, keloid scars form spontaneously.
Although they can be a cosmetic problem, keloid scars are only inert masses of collagen and therefore completely harmless, painless, and non-contagious. They tend to be most common on the shoulders and chest. Keloid scars are most common among Asians and Blacks.
Alternately, a scar can take the form of a sunken recess in the skin, which has a pitted appearance. These are caused when underlying structures supporting the skin, such as fat or muscle are lost. This type of scarring is commonly associated with acne, but can be caused by chickenpox, surgery or an accident.
Scars can also take the form of stretched skin. These are caused when the skin is stretched rapidly (for instance during pregnancy, or adolescent growth spurts), or when skin is put under tension during the healing process, (usually near joints). This type of scar usually improves in appearance after a few years.
Treatments for skin scars
No scar can ever be completely removed. They will always leave a trace, but their appearance can be improved by a number of means, including:
Some suggest that using creams containing Vitamin E, taking vitamin E supplements, or including plenty of vitamin E in a diet from sources such as wheat germ, nuts, vegetable oils, eggs and green vegetables, can help speed up the healing process, and lessen the appearance of any scar afterwards.
Other research, however, suggests that applying Vitamin E to post surgical scars does not reduce the size, shape, or color of scars and can, in up to one third of patients, result in contact dermatitis, allergic reactions, or other irritation that can worsen a scar's appearance. (Source: Baumann, Dermatologic Surgery, 1999. Also: )
There is also a suggestion that cocoa butter cream can be used to help heal scars, and to prevent the formation of keloid scars.
Any surgical scar removal will always leave a new scar that will take up to two years to mature. Surgery can never remove a scar but can be used to alter its alignment or shape to make it less noticeable.
Surgery can sometimes make the scar bigger, but improve its overall appearance. Surgery can sometimes be necessary to remove a scar on skin near a joint where it restricts movement.
In the case of hypertrophic or keloid scarring, surgery is not recommended, as there is a high risk of re-occurrence of possibly worse scarring following surgery.
Laser Surgery & Resurfacing
The use of lasers on scars is experimental treatment, the safety or effectiveness of which has not yet been proven.
The redness of scars may be reduced by treatment with a vascular laser. It has been theorised that removing layers of skin with a carbon dioxide laser may help flatten scars, although this treatment is still highly experimental.
A long term course of steroid injections under medical supervision, into the scar may help flatten and soften the appearance of keloid or hypertrophic scars.
The steroid is injected into the scar itself and very little is absorbed into the blood stream, side effects of this treatment are minor. This treatment is repeated at 4-6 week intervals.
Pressure garments should be used only under supervision by a medical professional. They are most often used for burn scars that cover a large area, this treatment is only effective on recent scars.
Pressure garments are usually custom-made from elastic materials, and fit tightly around the scarring. They work best when they are worn 24 hours a day for six to twelve months.
It is believed that they work, by applying constant pressure to surface blood vessels, after a long period of wearing one scars flatten and become softer.
Low-dose, superficial radiotherapy, is used to prevent re-occurrence of severe keloid and hypertrophic scarring. It is usually effective, but only used in extreme cases due to the risk of long-term side effects.
Dermabrasion involves the removal of the surface of the skin with specialist equipment and usually involves a general anaesthetic. It is useful when the scar is raised above the surrounding skin, but is less effective with sunken scars.
Collagen injections can be used to raise sunken scars to the level of surrounding skin. Its effects are however temporary, and it needs to be regularly repeated. There is also a risk in some people of an allergic reaction.
There are also a number of gel sheets available which are usually made from silicone, which can help to flatten and soften raised scars if worn regularly. Silicone, pressure, occlusion, topical cortisone and vitamin E have all been shown to decrease the collagen that forms scars. Patches and pads help but are unsightly so people tend to quit. The most popular treatment among plastic surgeons is Scarguard, a liquid that dries to a clear plastic film and contains silicone, a mild cortisone and vitamin E.
See also: scar tissue , scarification, plastic surgery, dermatology