"One of the things that most cosmetic surgeons do not realize is that you can actually affect different layers of the skin with peels, says Suzan Obagi, M.D., assistant professor in dermatology at the University of Pittsburgh Medical Center, Pittsburgh. "Depending on which agent you choose, you can have epidermal or dermal effects. Knowing that effect allows you to choose the agent correctly for the problem that you want to address."
Choosing the right peel"In skin with normal color, melanocytes are evenly spaced out; in freckled skin or skin with melasma, there are abnormal aggregates of melanocytes and overproduction of pigment," she says. "So issues of pigmentation are mainly epidermal and physicians do not have to reach the dermis to treat them. They can use salicylic acid or glycolic acid peels to address the surface layers."
Cosmetic surgeons who aim to treat wrinkles, acne scars and skin firmness need to reach deeper, into the dermis that contains collagen, elastin and glycosaminoglycans. Injury to the dermis resolves in a wound-healing response that produces additional collagen and elastin.
"The safest agent to use reproducibly, in this case, is trichloroacetic acid, or TCA," Dr. Obagi says.
Why choose peels?
Done correctly, an application of several medium-depth peels can achieve results close to what laser resurfacing can do, according to Dr. Obagi.
Peels can be an ideal solution versus laser resurfacing for people with darker skin types, who might be at risk for hypopigmentation from laser treatment. And even when laser resurfacing is appropriate, patients might not need a full-face laser. In that case, laser resurfacing combined with chemical peeling helps to rid patients of lines of demarcation for a seamless result, Dr. Obagi says.
"One of the biggest problems I see is when doctors peel a cosmetic subunit, such as the periorbital region or the perioral region, and leave drastic lines of demarcation between that area and the adjacent cheek area," she says. "The objective of cosmetic surgery is not to have any telltale signs that you have done a procedure."
Cosmetic surgeons can also combine peels with noninvasive lasers to get improvement in telangiectasias, lentigines, melasma and acne scars. Or they can use peels on nonfacial skin — such as the arms, legs, chest — that would not necessarily have a good result with lasers, Dr. Obagi says.
Successful skin peeling starts with pre- and post-conditioning programs. Preparing the skin can be the most important step in the process, she says. Pre- and post-conditioning enhances wound healing and prevents problems with hypo- and hyperpigmentation.
"You also get a more uniform peel when you are doing a chemical peel, if you prepare the skin weeks prior," Dr. Obagi tells Cosmetic Surgery Times.
Dr. Obagi uses sun blocks and topical agents, including Retin-A, hydroquinone and alpha-hydroxy acid, for at least four to six weeks before and after peeling. For darker skin types, she uses the agents for about three months, prior to and post peel.
Choosing right concentration
Cosmetic surgeons can chose among high concentration peels to get to their endpoints quickly and with the least amount of safety margin, or they can use lower concentrations and administer them more slowly, watching the skin carefully in order to stop when appropriate. The lower concentration approach, according to Dr. Obagi, is more reliable and safer than using high concentration peels.
Dr. Obagi, who uses the medium-depth Obagi Blue Peel, says it is wise to replace several vials with different concentrations of TCA, from 10 percent to 100 percent, with one working concentration of the peel.
"I often get consulted on cases where a doctor uses the wrong peel strength on a patient and causes a deep burn without realizing it," she says. "Peel vials are identical regardless of concentration, and the liquids look the same when you pour them into your dish."