Facial Chemical Peels including Trichloroacetic Acid (TCA) and Phenol
Chemical peels are divided into three broad categories based on the depth of action of the chemical: superficial, medium depth, and deep. Superficial peels are used to exfoliate the skin and are aimed at the most outer layer of skin and the overlying dead skin cells. Medium depth chemical peels work well for age spots, patients with melasma, and some superficial wrinkles. For patients with significant wrinkles, deep chemical peels or resurfacing laser treatments should be undertaken.
Any chemical peel must be used very carefully in patients with dark skin types. Deeper peels in dark skin types can produce permanent light patches of the skin and can have disastrous results. Even more superficial peels should only be used by physicians with experience in dark skinned individuals.
Patients who are undergoing or have recently completed treatment with isotretinoin (Accutane®) should not undergo chemical peels. Most physicians suggest at least 6 months and probably 1 year elapse before any skin resurfacing after isotretinoin use.
It is imperative to have a consultation with a qualified physician before undergoing any chemical peel procedure. Some skin areas which appear to be age spots may actually be early stage skin cancers and can be masked by the chemical peel. Evaluation by a dermatologist may be necessary before any treatments are undertaken.
With the advent of the internet, some of the more concentrated peel solutions are available for direct consumer purchase. These should not be used at home and should only be used by trained and experienced professionals. Permanent skin scarring and color changes can occur with any chemical peel. Follow up care and application by a trained physician is essential for a positive outcome.
Superficial Facial Chemical Peel
Superficial peels are generally aimed at rejuvenation of the outer layer of skin and sloughing of any dead skin. The most commonly used compounds for superficial chemical peels are alpha hydroxyl acids. Alpha hydroxyl acids are usually naturally occurring fruit acids, including glycolic, lactic, citric, tartaric, and malic acid. The most popular form used is glycolic acid which is derived from sugar cane. AHA’s are available over the counter though the concentration is less than those used by physicians, usually 3-10%. Physician applied AHA’s may have concentrations of 50% or greater. In physician application, the compound used is applied to the skin. The length of time left on the skin determines the depth of penetration. The solution is deactivated with application of a bicarbonate solution or washing with water.
Superficial chemical peels can also be accomplished with Jessner’s solution. Jessner’s solution is composed of resorcinol, salicylic acid, lactic acid, and ethanol. Application of Jessner’s solution produces a light frost of the skin which identifies when the appropriate depth of penetration has been achieved.
After application of either solution, redness will appear and sometimes a small amount of swelling. Over the next several days the outer layer of skin will slough off and re-epithelialization will usually be complete in about a week.
Superficial chemical peels are often used before deeper peels to remove the dead layer of outer skin and allow the deeper peels to produce a better result. Sometimes, a physician may suggest a patient use a low concentration AHA system for several weeks before or possibly as a maintenance therapy after deeper chemical peeling or laser resurfacing treatment.
Medium Depth Facial Peels
Medium depth peels are usually performed with 20-35% trichloroacetic acid (TCA). The depth of penetration is dependent on the concentration with higher concentrations creating deeper penetration. As TCA works, a white frost is formed on the skin which identifies the end point of application. When TCA is applied, the skin will burn but this can be neutralized with topical lidocaine or fanning and resolves within about a half hour. Exfoliation occurs over several days and complete re-epithelializiation usually takes about two weeks. During this time the skin will be red and will flake.
Deep Facial Chemical Peel
Phenol is considered the chemical of choice for deep chemical peels. Phenol is mixed with various other additives to create a formula which is actually used for the peels. Common formulas include Baker-Gordon, Venner-Kellson, Maschek-Truppman, and Grade. Formulations are necessary because as the concentration of phenol increases, the depth of the peel decreases to a point. By adding other chemicals to the peel, a deep peel can be accomplished. Application of phenol peels is usually performed with some form of anesthesia, possibly even IV sedation.
Phenol peels require medical cardiac monitoring as phenol can cause arrhythmias which can be fatal. Phenol is absorbed through the skin, metabolized by the liver, and subsequently excreted by the kidneys. Patients receiving phenol treatments usually have an intravenous line started and receive significant hydration to avoid toxicity.The face must be divided in 6-8 regions and at least 20 minutes must be allowed to elapse between finishing one area and starting another.
At the end of the procedure, the patient will have marked redness of the skin which can take several months to completely resolve. Discomfort is usually minimal after the first 24 hours. Re-epithelialization is usually complete in about 2 weeks.
Care After Facial Rejuvenation
Chemical peels not only wound the outer layer of skin but also decrease the body’s natural defense system by wounding skin. After care is aimed at keeping a moist environment for wound healing and preventing infection. Until the skin has completely re-epithelialized, moisture (in the form of petroleum based cream or other formulas) must be applied to the skin to keep the area moist. A dry environment can lead to unsightly scarring.
For medium to deep chemical peels, antibiotic medications and sometimes antiviral medications are prescribed. While not causing cold sores, chemical peels can cause enough of a body shock to cause a flare up of cold sores. Antiviral medications aimed at preventing or controlling cold sores should be used especially in those people with a history of cold sores.
If the skin starts to slough, patients are strongly warned not to pick the face but to allow the skin to fall off on its own. Soaks with some type of antimicrobial are used shortly after the peel to keep the area clean. Some physicians use vinegar or hydrogen peroxide for this purpose.
Just before and immediately following treatment, patients must be very careful about sun exposure. For several months after treatment, patients must use sun precautions (sunscreens, hats, glasses) when out in the sun. Excess sun exposure can produce hyperpigmentation (dark spots) and sometimes additional scarring.
In the immediate post treatment period until the skin has re-epithelialized, patients must avoid application of any make-up, sunscreen, soaps, moisturizers, or any other things not specifically approved by the treating physician. Application of such compounds can cause prolonged redness, drying of the skin, unexpected reactions, and in the worst cases, scarring.
Patients undergoing medium to deep chemical peels require close follow up to ensure that any unexpected complications can be quickly dealt with.