Chemical Peels in the Asian Patient
Patients with darker skin tone have many options for skin care especially in regard to chemical peels. When applied carefully and selectively they can correct fine lines, blemishes, acne, acne pigmentation, and dry dull complexions. This article appears in the Newsletter of the Indian Association of Plastic Surgeons, October 2010.
PERSPECTIVES ON CHEMICAL PEELS IN THE ASIAN PATIENT
(Author: Donn M.Hickman MD
Long Beach, California USA
Chemical peels for skin rejuvenation have seen a resurgence in popularity as the cost of expensive energy-based technologies challenges Aesthetic Skin practices to seek other cost-efficient treatments. A chemical peel does not have the “whiz and bang” of the laser peel which represents a panoply of the electromagnetic spectrum. The focus of modern skin resurfacing is on mitigation of the natural inflammatory response of the burn which can dispatch scar and hyperpigmentation. The special aesthetic purpose of each modality is therefore optimized.
As civilizations expanded to more agrarian occupations especially in the middle latitudes, increased sun exposure lead to genetic changes including production of p53 tumor suppressor gene, that counteracted the damaging effects of ultraviolet light on DNA and in turn caused the skin to tan. Darker skin demonstrated increase in the degree of melanization of the melanosomes but not an increased number of melanocytes. A natural sun block evolved. Photo aging in dark skin types shows fewer wrinkles, but more blotchy pigmentation over time.
The common bleaching agents used today for dyspigmentation are based on interference with the pathways in this melanization process. The fair-skin high latitude civilizations have, by a relaxed natural selection, lost their relative ability to tan due to a genetic defect in the skin protein, melanocortin-1 receptor which is critical for production of melanin. The sunscreen scientists, who have come to the rescue, have another problem on their hands. The daily use of sunscreens with various UV filters can inhibit the metabolism of Vitamin D and thus lead to decreased melanin production. It is therefore recommended that skin barrier creams with CM-glucans be added. These accelerate skin defenses, battle oxidants, and offset UV damage by a direct effect rather than as a filter. The intended UV defenses of the melanin barrier are preserved with this sunscreen combination.
The treatment of ethnically dark skin requires a fundamental understanding of depth of penetration first, and then the special properties of each peeling agent which act at various depths. The primary indication for peels in dark skin is hyperpigmentary dyschromia or blotchy skin. Other benefits include photo damage, post inflammatory hyperpigmentation, acne, scarring, and melasma.
While acne can be nicely treated in oily dark-skinned patients with glycolic acid and salicylic acid, northern pacific fair-skin Asian patients may be more sensitive to glycolic acid which is more irritating and complicated by post inflammatory pigmentation in skin types IV-VI. For those who are sensitive to Salicylic acid in ethanol, a preparation in polyethylene glycol solution (macrogol) is preferred. All-Asian dark-skin patients with dry pigmented skin in evidence by a gray tint to the dark skin because of desquamation, may be sensitive to the more irritating glycolic peels. Other peels which are less irritating to dry and oily All-Asian skin include lactic acid, mandelic acid, and pyruvic acid. Remember too, that all skin will be dryer in colder weather. In general, for All-Asian skin, use of low strength repeat peels is recommended and these may include TCA 10-30% alone or in combination with Glycolic Acid, and Jessner’s solution. Jessner’s is particularly useful since it is formulated to lower the toxicity of its 3 ingredients (resorcinol, lactic acid, and salicylic acid) while optimizing the penetrative and exfoliative effects of each. For melasma, serial treatments of glycolic at the same low concentration can work well, but again, salicylic acid might work better. Acne scarring can be nicely treated with low concentrations of TCA, but the use of Dermabrasion over 30% TCA, can be very effective, for serial treatment in darker skin types. Minor pigment change is well tolerated in these All-Asian patients with Type IV-VI skin.
It is critical to consider preparation of the skin for All-Asian patients particularly those with the most significant dyschromias as they may react the most after treatment. Use of Triluma cream or Kligman’s solution for 3 to 6 weeks is highly suggested. The patients are informed that some early pigmentation is a natural result of resurfacing, and tolerate this well when deploying skin bleachers, low dose steroids, and a retinoid. Due to reports of complications with prolonged unchecked exposure to hydroquinones, in Asia, the use of kojic acid may be preferred. Also effective are Azelaic Acid, and Nia-24 (niacin) skin care products for pigment control.
While glycolic, salicylic, Jessner’s, and serial low- concentration TCA are the most popular peels for All-Asian skin types, some of the least mentioned peels may be very effective:
. Lactic acid, from soured milk, the least drying of the AHAs,. is a natural part of the acid protective mantle of the skin keeping the pH at5.5 to 6.0. It stimulates ceramide production which is 1 of the 3 ingredients of the stratum corneum skin barrier. It is excellent for dry skin types of non-pigmented and pigmented skin. It also limits tyrosinase conversion to melanin thus reducing pigmentation. (20-40% and can move to 90% in serial treatments beginning at 1-2 minutes)
Pyruvic acid, a derivative from honey and fermented fruits, rapidly penetrates skin at its low pH and pKA but it is a low irritant due to its conversion to lactic acid. It is curiously sebostatic, slowing down oil production and is excellent for use in papulopustular acne with inflammatory pigmentation. It is also effective in melasma. It penetrates into hair and oil glands by being so lipophilic. At greater than 50% strength its penetration is unpredictable and precarious. Currently it works best at 40-50% in balanced water-ethanol solution. It is often mixed with lactic acid in peeling solutions. (40-50% peels can be done every two weeks at 1-2 minutes to start) Mediterranean and Indian literature highlights its use in acne and melasma.
Mandelic Acid, derived from the hydrolysis of bitter almonds is antiseptic, with low irritation (good for dark dry and dark oily skin) compared to glycolic acid, and controls oil production with a very low incidence of reactive hyperpigmentation. It penetrates better and more prolonged in macrogol gel solution. It can also be found with lactic acid in combination to diminish irritation. (30-50% peels every two weeks, starting at 1-2 minutes each). Indian literature highlights 10% mandelic-30% salicylic acid peels for acne and post-acne pigmentation. .
Betalipohydroxylic Acid, a derivative of salicylic acid is a potent acne agent and pore cleaner, and impairs bacterial fixation.