Keloids and Hypertropic Scars 'Ba Hen Ge Da'
An alternative view of collagen mass
The high recurrence rate of keloids has initiated a wide variety of different treatment approaches. Thus far, convincing evidence does not exist to recommend any therapy over surgical excision followed by sequential intralesional steroid injections; however, well-controlled studies on the treatment of keloids are rare. Radiation therapy is reserved for keloids recalcitrant to conventional therapy.
The favored treatment regimen for hypertrophic scars is surgical excision. The response is generally more favorable than that with keloids, as long as the initial negative influences on healing are not reproduced. The use of intralesional steroid injections in hypertrophic scarring remains questionable. The risks and benefits must be weighed and clearly explained to the patient.
Keloids treated with simple excision have a recurrence rate ranging from 50-80%. The use of Z-plasties or any wound-lengthening technique for excising keloids is strongly discouraged. Complete excision and near-total excision (ie, leaving behind a small remnant of keloid on the peripheral portions of the incision) have both been advocated. The theoretical benefit of the latter is that previously uninjured tissue is not traumatized, decreasing the chances of recurrence; however, whether the residual keloid remnant contributes to further keloid development remains unclear. Wide undermining should be used to make closure of these wounds tension-free. Provided that adjacent tissue is manipulated, wide undermining may or may not increase the risk of keloid recurrence.
The use of cuticular, monofilament, synthetic permanent sutures is advised to decrease tissue reaction. Tissue adhesives may provide a less reactive skin closure, which may decrease the likelihood of keloid formation.
Lasers, such as carbon dioxide, pulse dye, neodymium-yttrium aluminum garnet (Nd-YAG), and argon, have been used as alternatives to cold excision for keloids; however, the use of lasers is expensive and cumbersome. Superiority of laser use to simple excision currently has not been demonstrated in clinical trials. Further research and technologic developments may enhance the effectiveness of lasers to treat keloids in the future.
Cryosurgery is a form of ablative modality proposed by certain authors. Zoubolis et al reported a good or excellent response in 61% and poor or no response in 39% of keloid study participants (n=55). The mechanism of action of cryotherapy involves the use of a refrigerant to induce a frostbite-type injury with cellular damage and vascular sludging. The period required to achieve a response is significant, 2-10 sessions separated by 25 days. One of the main adverse effects is hypopigmentation due to injury to melanocytes in the basal layer of the epidermis.
A commonly used steroid is triamcinolone injected directly into the scar. This works by increasing the activity of an enzyme called collagenase. This enzyme breaks down collagen so that scars become less thick and red. The steroid does not change the amount of collagen made by the cells nor does it decrease the number of cells making collagen. Its action is primarily to remove some of the excess collagen from the wound. However, this alone is not able to prevent a future proliferation of scar tissues.
The direct infiltration of various forms of cortisone is the most used therapy for scar treatment. The effect of cortisone is (at least partly) the blockade of the iNOS transcription, and therefore a reduction of the collagen production in fibroblasts and a reduction of the alpha2-macroglobulin synthesis (an inhibitor of the collagenesis). In most cases Triamcinolonacetonid (TA) 10-40 mg in pure form is injected. The earlier the treatment starts the better are the prospects of success.
Possible side effects: (especially with the wrong injection technique) includes atrophy of the sub-cutis, change of pigments, teleangiektasis (visible dilated vessels on the skin surface). There is no proof of the effectiveness of topical cortisone creams, ointments or plasters.
Steroids are not usually used immediately after surgery because they decrease inflammation and weaken the wound. In severe scars the benefits of injecting the steroid immediately may outweigh the risk of weakening the scar.