With advances in the knowledge of wound healing, as well as the development of better materials and techniques, many options have become available in the treatment of patients with unsightly scars. Nevertheless, no technique has been devised to allow for total and permanent elimination of scars. Patients should be counseled to understand that the goal of scar revision is to replace one scar for another to improve the appearance and the acceptability of the scar.
The wound healing process is divided into three stages. In the inflammatory phase, the release of inflammatory mediators results in migration of fibroblasts into the wound. During the proliferative phase, an extracellular matrix is formed that comprises proteoglycans, fibronectin, hyaluronic acid, and collagen secreted by fibroblasts. Angiogenesis and re-epithelialization of the wound also occur during the proliferative phase. Collagen and the extracellular matrix mature in the remodeling phase, and the wound contracts. Wound strength reaches 20% of its preinjury strength at 3 weeks. The ultimate tensile strength of the wound is 70–80% of that of the uninjured skin.
Genetic factors contributing to poor scar formation are likely to be present in patients with Fitzpatrick skin Types III and above. Darker skins tend to form postinflammatory hyperpigmentation and are more likely to form keloids or hypertrophic scars. Younger skin has more tensile strength, which can lead to widening of the scar, whereas older skin tends to scar better because of a lesser amount of tension on the wound.
Iatrogenic causes of poor scar formation include excessive soft tissue trauma while handling the skin, failure to reapproximate and evert the wound edges properly, and closure under excessive tension. Failure to evert the wound edges at the time of closure leads to formation of a depressed scar. Lack of deep support of the wound can lead to excessive tension on wound edges, resulting in a widened scar. Sutures from facial wounds should be removed after 5–7 days. Removing sutures too early or too late may lead to a wide scar or unsightly tracking, respectively. Early treatment with steroids or isotretinoin (Accutane) can adversely affect wound healing. It is recommended that laser resurfacing procedures or elective surgery, especially on the face, be delayed for at least 12–18 months after completing a course of isotretinoin.
Hypertrophic Scar, Keloids, and Widened Scars
Hypertrophic scars are self-limited scars, which hypertrophy within the limits of the wound but above the skin level. Hypertrophic scars are more common than keloids and occur without race predilection and in any age group. Initially, these scars are red, raised, pruritic, and occasionally painful, but they tend to flatten over time. They appear worse at 2 weeks to 2 months after wound closure. In general, hypertrophic scars are more responsive to steroid injections than are keloids.