Chemical peeling is emerging as one of the most effective ways to combat skin aging. Chemical peels are one of the most frequently performed aesthetic procedures in North America. Its popularity continues to grow because of the versatility of conditions where chemical peels are of significant benefit. In addition to the topical preparations such as over-the-counter and prescription creams, chemical peels are one of the earliest forms of treatment adopted by many patients. At the same time, there is much confusion and misunderstanding surrounding chemical peels that prevents more of us from enjoying their undeniable benefits. Let’s go through the important facts about chemical peels and their uses in modern skin care regimens.

Categories of Chemical Peels:

1. Superficial chemical peels:

Broadly speaking, chemical peels can be divided into several categories based on the depth of penetration in the skin. Superficial chemical peels create an injury to the epidermis – the outermost layer of the skin. As such, they are recommended for the treatment of skin conditions that primarily affect the epidermis. Conditions such as acne, actinic keratosis, superficial (epidermal) melasma, mottled skin pigmentation, superficial wrinkling as well as mild photo-damage can greatly benefit from properly selected and applied superficial chemical peels.

* AHAs

Some of the most common examples of superficial chemical peels include a variety of alpha-hydroxy acids
(AHA,) salicylic acid as well as low concentration trichloroacetic acid (10% – 25%.) The most commonly used superficial chemical peels are members of AHA. Alpha-hydroxy acids is a group of compounds derived from food products including glycolic (from sugar cane,) lactic (from sour milk,) malic (from apples,) citric (from fruits) and tartaric acid (from grape wine.) Glycolic acid (GA) is a clear winner amongst the AHA as its small molecular weight allows it to penetrate into the skin and exert its influence on living and non-living (outermost layer) cells. These properties account for the popularity of this product in both cosmetic as well as medical preparations.

In low concentrations, 5 – 10%, GA reduces cell adhesion in the top layer of the skin. This action promotes exfoliation of the outermost layer of the skin accounting for smother texture following regular use of topical GA. This relatively low concentration of GA lends itself to daily personal use as a monotherapy or a part of a broader skin care management for such conditions as acne, photodamage, wrinkling as well as selected cases of melasma.

In higher concentrations, between 10 and 50%, the benefits of GA are more pronounced but are limited to temporary skin smoothing without much long lasting results. This is still a useful concentration to use as it can prepare the skin for more efficacious GA concentrations (50 – 70%) as well as prime the skin for deeper chemical peels such as higher concentration trichloroacetic acid.

At higher concentrations, 50 – 70% applied for 3 to 8 minutes under the supervision of a physician, GA promotes separation between the cells and can be used to treat acne, photodamage (such as mottled dyspigmentation, superficial melasma or fine wrinkles) as well as superficial scars. The benefits from such short contact application depend on the pH of the solution (the more acidic the product [lower pH,] the more pronounced the results,) the concentration of GA (higher concentrations produce more vigorous response,) the length of application and prior skin conditioning such as prior use of topical vitamin A acid products. Although single application of 50 – 70% GA will produce beneficial results, multiple treatments every 2 to 4 weeks are required for optimal results.

* Salicylic Acid

Salicylic acid is a member of beta-hydroxy acid group. Because of its improved lipid solubility compared to the AG, it is particularly effective in the treatment of acne. In addition, it is not as inflammatory and some physicians use it extensively for the treatment of melasma. Low concentration trichloroacetic acid (10% – 25%) can also be used to treat the conditions affecting superficial epidermis but its use is limited to experienced physicians as more detailed patient selection and application care is required. As such, physician supervision is required for all peels except low concentration glycolic acid (up to 35%) and salicylic acid peels (below 20%.) This precaution is necessary to prevent inadvertent worsening of the skin condition as well as scarring.

Although in some instances only one superficial peel can accomplish desired effects, in most cases a series of peels is recommended to achieve optimal results. Superficial peels are an excellent way to introduce oneself to the rejuvenating power of these common aesthetic procedures. Done properly and with care, superficial peels are very safe treatment options for some of the most common conditions affecting facial skin.

It is important to understand that superficial chemical peels are peels with similar risks and side effects as other peels. Some of the side effects of superficial chemical peeling can include hyper- or hypo-pigmentation, persistent redness, scaring as well as flare up of facial herpes infections (“cold sores”). Caution needs to be exercised with some patients, particularly those suffering from rosacea or eczema. These patients are prone to skin irritation and even the mildest peels can cause injury to the skin. Fortunately, in most instances, such injury can resolve with time and optimal skin care. In cases of melasma, extreme caution needs to be taken, as it is possible to worsen this common and unforgiving skin condition. Any significant redness of the skin must be avoided.

Author: Mariusz J.A. Sapijaszko, MD FRCPC (Dermatology)