All full thickness wounds of the skin heal by scar formation. This is true regardless of who closes the wound and how well it is done. A scar is an inevitable consequence of an injury that is deep enough to require sutures. Proper treatment cannot prevent a scar, but it can make it less noticeable.

There are many factors that influence the severity of a scar. Certain areas of the body are notorious for poor scarring - the shoulder, knee, and sternal areas, for instance. These areas are under a lot of tension and motion. In general, the less tension on the wound, the less the scar will widen with time. If there is a lot of tissue loss and the wound must be closed under tension, this will lead to a poor scar. If the surrounding tissues are contused, and the zone of injury is large, the scar will be poorer. These are things that the doctor and the patient cannot control.

There are factors that are under the doctor's control. Devitalized tissue should be debrided, both to prevent infection and to decrease scarred tissue. Foreign bodies (dirt, glass, etc.) should be removed, since they predispose to infection. In deep wounds, multiple layer closure will eliminate dead space and will decrease tension on wound edges. Choice of suture can influence the final scar. In general, one would choose the finest suture that will hold the wound together, and use a suture that causes the least inflammatory response. Absorbable suture causes more inflammation than non-absorbable suture. Monofilament suture causes the least inflammation. Removing sutures promptly helps prevent suture tract scars, which can be more noticeable than the scar itself.

KELOIDS AND HYPERTROPHIC SCARS
Although they can look similar, hypertrophic scars and keloids are not the same. Both are the result of excessive collagen formation in the wound, and look the same histologically. A hypertrophic scar stays within the boundaries of the wound; a keloid extends beyond the wound itself.

Hypertrophic scars are common, especially in children and in fair skinned people. They are red and raised and can be itchy. In these scars, there is an imbalance in collagen synthesis versus collagen degradation. In all healing wounds, new collagen forms and some remodels and is broken down. In immature wounds and hypertrophic scars, more collagen forms than is broken down. In the majority of cases, this is temporary and resolves without treatment (though it may take a year or more). Steroid injections can control itching, but may make scar spread more. Silicone gel sheeting can be effective, but must be used on the wound for at least 12 hours a day. This is available without a prescription, but is relatively expensive ($30-50 for most small wounds).

Keloid scars are caused by uncontrolled collagen proliferation. They are most common in those with African and Asian descent, but can occur in all races. Some people are highly susceptible to keloid formation and form keloids with even minor scratches. These people are almost certain to form keloid in a wound, and consideration should be given to early referral. The best way to minimize the risk of keloid formation is to optimize wound healing as noted above. Even a perfectly treated wound can form a keloid in a susceptible individual. If a keloid is beginning to form, it can often be suppressed with injections of triancinolone into the scar (10-40 mg every 6 weeks as needed).

TREATMENT OF ESTABLISHED SCARS
Scars cannot be "removed." They can be made less noticeable by redirecting them, evening out high and low spots, or by redoing them under better conditions for healing. Time can also be a great ally. If the scar seems unacceptable, a plastic surgeon should evaluate it. Unfortunately, insurance coverage for scar improvement can be difficult to obtain. Plastic surgeons find it very helpful when the primary physician's office records can support patient complaints of symptoms or functional problems that might convince an insurance company to cover a procedure.