General Medical Information

Keloids and Hypertrophic Scars

David J. Terris

A keloid is defined as the production of an overgrowth of dense fibrous scar tissue that extends beyond the borders of the original skin injury. Hypertrophic scars, by contrast, may be associated with the deposition of excessive scar tissue, but this scar tissue remains within the confines of the original cutaneous injury. Unlike hypertrophic scars, which may undergo some degree of wound contraction, keloids do not flatten or regress, and they may occur spontaneously. Promising work at the molecular level has already demonstrated elevated levels of TGF-b1 and TGF-b2 in the fibroblasts from keloids, compared with fibroblasts from normal tissues. Continued molecular investigation is likely to yield a greater understanding of the cause of keloids and hypertrophic scars and may lead to potential mechanisms for treatment.

Several techniques have been proposed to treat keloids, and their number reflects the disappointing results of any given approach. These include intralesional steroids, cryotherapy, radiation therapy, laser therapy, elastic compression garments, and silicone gel sheeting. Retrospective studies have suggested a role for either radiation therapy or triamcinolone after surgery, but convincing data supporting these modalities have only recently been reported. Sclafani completed a prospective randomized investigation comparing steroid injections and radiation therapy for the treatment of keloids. Although there was no control group or blinding, their study allowed the most confident comparison between radiation and triamcinolone; radiation therapy was proved to be superior. This conclusion must be tempered against the costs and risks of radiation therapy, including injury to normal tissues and induction of neoplasia.

Innovative techniques for the treatment of keloids are being explored, including the use of cultured keratinocyte grafts, although these remain experimental models. Other therapies that have been tried include surgery combined with radiation or steroids and interferon-a2b, which, when combined with surgery, offers a mere 8% recurrence rate. Such combination therapies appear to provide the best chances for preventing recurrences of keloids.