Proper preconditioning key to effective chemical peel
Although she works in a university-based cosmetic surgery practice where she has access to 14 different lasers, Dr. Obagi says she still performs the entire spectrum of chemical peels, from superficial to deeper phenol-based procedures.
"The more lasers we get, the more I am reminded about the benefits of chemical peels. They can be used alone or in conjunction with other rejuvenating procedures, but, relative to laser procedures, chemical peels offer a less-expensive, better-tolerated modality that can address a host of different skin problems in patients of all skin types and with less post-treatment morbidity," says Dr. Obagi, associate professor of dermatology and director, Cosmetic Surgery & Skin Health Center, University of Pittsburgh, Pittsburgh.
"However, success with chemical peeling requires choosing the right peel for the right patient, along with proper preconditioning to get the skin in the best shape possible," she says.
Dr. Obagi says all her patients are given antiviral medication as prophylaxis for herpes reactivation. However, the dosing is adjusted based on history of outbreaks. Determining mental stability is important for deciding whether the patient will be compliant with postprocedural instructions or likely to do something that will impede recovery and increase the risk of complications.
A history of keloids and hypertrophic scarring also should be elicited. This finding does not present an absolute contraindication, but suggests that, for safety reasons, the peeling depth should not go below the papillary dermis. Use of isotretinoin is also relevant in this regard, as it is associated with an increased risk of developing keloids or hypertrophic scarring after peeling procedures involving the reticular dermis.
"Lighter peels can still be done safely within three to six months after stopping isotretinoin," Dr. Obagi says.
SKIN EVALUATIONS The skin evaluation assesses skin thickness, which influences decisions on depth of the procedure and the number of coats needed. Thicker skin is relatively richer in adnexal structures, so that regeneration will be better. Therefore, peeling into the reticular dermis can be done safely in thick-skinned patients, whereas it is better not to go deeper than the papillary dermis in patients with thinner skin. However, it is also important to recognize that to reach the same intended depth, additional coats of peeling solution will be needed in the patient with thicker versus thinner skin.
Oiliness also must be considered, because surface oil inhibits penetration of the peeling solution. Therefore, patients with very oily skin may be pretreated with isotretinoin or a noninvasive laser to reduce oil.
Assessment of skin color provides insight into the potential to develop pigmentary alterations after the peel. Within any ethnic group (other than Caucasian), those with lighter skin will more likely have unstable pigment after the procedure and be at greater risk for developing hyperpigmentation than their counterparts with darker skin. In Caucasian skin, the opposite is true, with brunettes having more pigmentation instability as compared to the light-haired and fair-skinned patient.
"If doing a lighter trichloroacetic acid peel, skin color will not exclude any patients from the procedure. However, it is a consideration in the length of the pre-peel skin conditioning program," Dr. Obagi says.
Skin laxity is also important to note, and in this regard, fragility must be differentiated from muscle laxity.
"Fragile skin is more prone to ecchymosis. In addition, the peel depth should be kept to the papillary dermis to minimize scarring risk in patients with fragile skin," Dr. Obagi says.
PREPPING THE SKIN The goals of the preconditioning regimen are to prepare the skin for improved penetration of the peel and faster recovery, but preconditioning also will improve skin appearance.
"Occasionally, the need for a peeling procedure may even be eliminated after a period of proper skincare. More often, the benefits achieved are impressive enough that the patient has added faith in your expertise and will be more compliant with their post-peel instructions," Dr. Obagi says.
The components of the conditioning regimen target keratinocytes, melanocytes and fibroblasts and include use of alpha or beta hydroxy acids as sloughing agents; retinoids to normalize keratinocyte turnover and promote collagenesis; and a tyrosinase inhibitor to prevent hyperpigmentation. Patients are also instructed to use a broad-spectrum physical sunblock daily alone or combined with topical vitamin C for added photoprotection, and to wear a broad-brimmed hat if they will be outside for longer than 15 minutes.
Dr. Obagi adds that she considers 4 percent hydroquinone the safest and most effective modality for inhibiting tyrosinase, and that the retinoid treatment must be administered with a prescription tretinoin or tazarotene preparation, as the over-the-counter retinol products do not have sufficiently potent effects on fibroblasts.
Dr. Obagi reports no relevant financial interests.