Since its infancy, literature has chronicled our desire to look younger. Some of the earliest prescriptions were elixirs for youth and salves designed to maintain a vibrant appearance.

However, a breakthrough came in the 1980s with the discovery of alpha hydroxy acids (AHA). These chemicals, when used in high concentrations as peels and at lower concentrations in daily care, reduced wrinkles and increased protein production in skin. In addition, a University of Michigan dermatology department study showed that topical tretinoin, a prescription drug, had similar results. The combination of these two phenomena, combined with the exquisite timing of the baby boom generation reaching middle age, finally allowed us to provide proven topical methods for turning back the clock.

Since then, various high-tech -reiterations have come center stage. Most recently, fillers and neurotoxins have dominated the field, pushing topical treatment further to the periphery. However, physicians who only center on these latest high-tech approaches are missing an important component of aesthetic practice. In a comprehensive treatment paradigm, chemical peels, whether as an office-based procedure or as an active ingredient in home-based products, remain just as relevant as the days before these newer approaches came on the scene.

Classification of Peels

Since the discovery of alpha-hydroxy acids, choices of chemical peels have multiplied and become increasingly sophisticated. Today, office-based peels are classified into superficial, medium and deep peels and are based on the approximate wound depth.

Superficial peels. Superficial peels pene-trate from the epidermis to the upper -papillary dermis. Superficial agents include glycolic acid (GA) up to 70 percent, trichloracetic acid (TCA) up to 20 percent, and Jessner's solution, which is a combination of resorcinol, salicylic acid, lactic acid and ethanol. These agents are effective for lentigines, inflammatory acne and post-inflammatory hyperpigmentation.

These peels do not produce frosting or self-neutralize. Rather, the health care provider controls the exposure time, depending on the desired depth. For example, mild acne and epidermal dyschromia will require shorter exposure times, while moderate photodamage will respond better to longer exposure times.

Neutralization is achieved with a sodium bicarbonate solution. Since this is an exothermic reaction, the patient may feel slight heat. The patient can then either rinse with cold water, or leave towels saturated with cold water on the face.

TCA is self-neutralized. Therefore, the penetration is related to the number of application coats, not exposure time. TCA application results in white frosting in approximately two minutes, indicating the completion of the peel. Patients will experience a burning discomfort during this process. Upon completion, water-soaked gauze or a towel is placed on the patient's face.

Erythema will persist for several days after the peel, depending on the depth. We sometimes prescribe mild topical steroids to reduce discomfort and the risk of post-inflammatory hyperpigmentation, especially for people with darker skin types.

We also tell patients to avoid retinoids for up to two weeks, until complete re-epithelialization. Some clinicians have started to offer specific wound healing creams and growth factor creams to hasten recovery.

Medium-depth peels—Medium-depth peels can penetrate the upper reticular dermis. Medium peels are characterized by TCA (35 percent to 40 percent) alone or in combination with Jessner's or 70 percent GA. TCA above 35 percent alone is less predictable, with increased risk of scarring and complications. When combined with GA or Jessner's, TCA achieves a more predictable medium-depth peel.

These peels are effective for dyschromia, photodamage, mild rhytides, scars and actinic keratosis. However, medium-depth peels require longer recovery, compared to superficial peels. In addition, collagen remodeling generally continues for several months.

Deep chemical peels. Deep chemical peels can penetrate to the mid-reticular dermis. They reduce severe rhytides and scarring and typically contain large concentrations of phenol. The most commonly available preparation is Baker's formula, composed of phenol, croton oil, septisol and distilled water. This is reserved for deep rhytides and severe photodamage only, due to the potential of cardiac arrhythmias, and renal and hepatic dysfunctions. Physicians usually administer intravenous access and sedation. Patients will need prolonged postoperative care. These potential complications have made phenol peels much less attractive to physicians, who are largely replacing this option with laser resurfacing.

Precautions for Peels

While techniques vary, certain universal precautions remain true for all peels.

As with any cosmetic procedure, patients need thorough counseling to manage their expectations. They need to understand they will have to undergo the full series of treatments to achieve the desired effect. They should also recognize that deep defects, such as scars and deep rhytides, are unlikely to improve.

Prior to the peel application, the skin must be thoroughly cleansed. Acetone is often used to remove excess oils. Ointment should also be placed at the corners of the eyes for protection. The patient's head should be elevated slightly to allow excess peeling agent to run away from the eyes.

Take precaution to evenly distribute the peeling agent, and avoid excess dripping and splashing. Applications of the peel should be systematic, finishing one anatomic region, such as the forehead, before moving on to the cheeks, chin and rest of the face. To allow even application in patients with severe laxity, the clinician should stretch the skin taunt.

Patients who have been on isotretinoin in the last six months should avoid medium and deep peels. Those with a history of herpes simplex virus outbreaks should take antiviral prophylaxis. In addition, make sure patients with rosacea or seborrheic dermatitis know they will likely have postoperative irritation and flare. Post-inflammatory hyperpigmentation is a risk in patients with a recent tan or those with skin types IV through VI. To avoid pigment alteration, patients must use photoprotection. This is paramount, especially during the treatment series.

Luckily, complications for chemical peels are rare. However, patients may experience prolonged erythema, cystic acne flare, colloid milia, pigmentary alteration and reactivation of latent herpes simplex virus. Hyperpigmentation can be effectively treated with hydroquinone and/or tretinoin. A short course of oral antibiotics helps improve inflammatory acne. In addition, colloid milia can be improved by simple extraction.

Home Care Preparations

A topical home regimen can be critical to optimizing the outcome of office peels. Certain manufacturers have produced physician-dispensed product lines that contain chemical peels agents at a lower concentration.

With physician-dispensed products, patients can continue reaping the benefits of their office-based procedures long after they leave the office. Patients also will have the confidence that the outcome of the office procedure will only be enhanced.

Patients look to us to provide more powerful at-home regimens and ingredients not found in over-the-counter (OTC) products. For example, the concentration of AHA cannot exceed 10 percent in OTC products, and the pH cannot be lower than 3.5. In contrast, physician dispensed AHA products may surpass 10 percent.

Biopelle Inc. of Ferndale, Mich., has introduced an acidified amino acid product line, called AFA.^®The product seeks to improve alpha hydroxy acid. This novel ingredient is synthesized by the acidification of naturally occurring amino acids.

Like AHA and other acid peels, such as kojic acid and glycolic acid, AFA promotes exfoliation. However, it appears to be less irritating since the amino group on the molecule gives it an alkaline pH, which is closer to the physiologic pH. It further helps retain moisture and offers antioxidant properties.

The product line consists of in-office peels of varying strengths and home use products. The primary benefit is that AFA causes less irritation and dryness, but may produce the same or even better cosmetic effects as with more irritating glycolic acid peels.

Allergan of Irvine, Calif., offers VIVITE^®with GLX technology. This physician-dispensed glycolic acid and antioxidant-based topical skin care regimen consists of an exfoliating facial cleanser, an antioxidant facial serum, a facial cream and an eye cream. A preliminary open-label, observer-blinded trial involving 24 women with mild to moderate facial photodamage reported a reduction in fine lines, dryness and roughness, with high patient satisfaction.¹The product claims not only to exfoliate the stratum corneum, but also to enhance the skin's natural production of hyaluronic acid and epidermal growth factor. It also claims to stimulate collagen production.

LaRoche Posay's Lipo-Hydroxy-Acid (LHA) is a new peel that takes advantage of the agent's particular affinity for the upper layers of the epidermis. The structure resembles salicylic acid, which targets intercellular lipids and disrupts corneodesmosomes, making it especially effective in skin exfoliation and cellular turnover. The lipophilic nature allows for it to stay in the epidermis for longer periods of time and has proven to be an effective treatment for acne. However, there appears to be slightly more irritation compared to conventional peels.

This is by no means an exhaustive list of new product lines containing both classic chemical peel agents and novel acidified agents. Ferulic acid (SkinCeuticals, a subsidiary of L'Oreal) is a new ingredient with both antioxidant and ultraviolet radiation protective properties. It is commonly found in natural food sources, such as rice, wheat, oats, coffee and apples. It contains a phenolic oxygen-hydrogen group that acts as a hydrogen donor to free radicals.

In addition, Obagi of Long Beach, Calif., offers the NuDerm system, which includes a product line that combines 4 percent -hydroquinone with AHA. It also has a tretinoin cream and a sunscreen to improve fine wrinkles, hyperpigmentation and laxity. Physicians should help guide patients in selecting the optimal home regimen based on their primary concern, the sensitivity of their skin and their budget.

Bringing Back the Peel

In-office and at-home chemical peels offered in combination can be especially effective for many patients. Even though chemical peels may have lost some luster in the face of newer, sexier laser options, they still have a place in total facial rejuvenation, especially as a complement to botulinum toxin and soft tissue fillers.

In recent years, we have underused this simple, low-cost option. But don't overlook what's right in front of you: Chemical peels offer a low-tech approach that can still produce high-level results. n

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