Chemical Peels - A Re-Emerging Art

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

The art and science of chemical peeling is re-emerging once again as one of the most effective methods of combating skin aging. Chemical peels are one of the most frequently performed procedures in North America. Its popularity grows because of the variety of benefits that it offers to various skin problems. Although it is one of the most popular treatments next to topical therapy such as OTC and prescription creams, there is much confusion and misunderstanding about chemical peels. What follows are important facts about chemical peels and their uses in modern skin care.

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. (e.g. Reversa ® product line) 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.

2. Medium depth chemical peels:

Medium depth chemical peels create an injury that extends through the epidermis and affecting the superficial portion of the dermis (upper reticular dermis). This category of peels includes higher concentration of TCA peels (35% - 50%,) Jessner's solution and carefully applied 88% phenol. In proper hands, these peels are very effective for the conditions that affect the epidermis as well as superficial portion of the dermis. Substantial improvement can be achieved in acne, actinic keratosis, scars, mild to moderate facial wrinkling and, in selected cases, in melasma.

The therapeutic effects of medium depth chemical peels go far beyond what can be achieved with superficial peels and as such are selected for patients who desire substantial results. Unlike following superficial chemical peels, there is partial or complete removal of the epidermis following medium depth peels. This leads to the initiation of skin healing mechanisms that are partly responsible for achieving final therapeutic and aesthetic results. Such impressive results do not come without increased risks. Skin irritation, infection, scarring, worsening of the treated problem (mostly seen with melasma) as well as pigmentary abnormalities are the most common problems that are seen following mid depth chemical peels.

Optimal patient's skin preparation prior to medium depth peel will improve healing time, decrease the chances of complications as well as improve the final outcome. As such, most patients can benefit from vitamin A acid derivative applied to the skin for several months prior to the medium depth peeling. This preparation enhances skin healing and decreases the chances of altered pigmentation following such peel. In addition, patients need to be initiated on antiviral therapy prior to the chemical peel and continuing until full skin re-epithelialization. This will decrease the chances of facial herpes infection that in some cases can lead to scarring. Post peel care is also an important part of patient management. In the first week following medium depth chemical peel, it is important to avoid drying of the skin. Generally speaking, patients are asked to apply moisturizing preparations and wash their faces regularly. Full skin re-epithelialization is usually achieved by day five following the procedure. In addition, sun protection in the future is advisable to help prevent pigmentary complications and maintain results. Although one medium depth chemical peel can achieve desired affect in most patients, repeated treatments may be needed to optimize the desired results.

3. Deep depth chemical peels:

Deep chemical peels create an injury that extends through the epidermis to the mid portion of the dermis. This category of peels includes 88% phenol under occlusion as well as Baker-Gordon formula. In trained hands, these peels are very effective for the conditions that affect the epidermis as well as the dermis. Significant improvements can be achieved in severe actinic keratosis and photodamage, scar management as well as moderate to severe facial wrinkling.

Deep chemical peels can offer significant benefits with the potential for producing amazing long-term results. In many cases, it is possible to achieve results that are similar to those seen with resurfacing lasers. However, they can only be used by trained physicians as they have a significant risk of complications. At this time, there are few physicians that are trained in the use of deep chemical peels. This is because of the introduction of resurfacing lasers to the market. The one major disadvantage of deep peels is that their safety margin is relatively small and the risk of complication is substantial. In addition to the complications inherent in medium strength peels, long lasting or persistent hypopigmentation is seen in patients quite commonly. For many patients, the impressive effect of skin smoothing is a worthwhile trade off.

Chemical Peels and Aesthetic Procedures:

Chemical peels are also an excellent addition to other aesthetic procedures. They can be used with the ongoing home personal treatment with lower concentration glycolic acid or vitamin A acid derivatives. Furthermore, they are an excellent addition to facial procedures such as blepharoplasty, face lift and laser skin resurfacing. It is frequently the combination of treatments that produces desired results as each facial concern is addressed with appropriate modality.

As with any aesthetic procedure, it is imperative that the patient discusses their motivations, desires, and fears. The pre-operative consultation is an important time to discuss these matters. Conditions affecting the epidermis can be treated using superficial peels, where as conditions that affect deeper skin will require medium or deep chemical peeling. It is important that the patient understand the relative risks and rewards, and expected down-time for the operations. All the factors contribute to proper patient selection and the optimal skin peeling agent. It is certainly possible, with proper patient selection and optimization of desired chemical peel procedure, to achieve patient satisfaction and rewarding sustained aesthetic result. Chemical peels are making a re-emergence, and have proved its efficacy.