Latest Chemical Peel Innovations

For decades, chemical peels have remained a trusted option for treatment of aging facial skin. However, emerging technologies are being adopted by many practitioners who may not have had sufficient opportunity to learn the art of chemical peeling. Properly performed peels can improve the condition of the skin, are less expensive than light-based machines, and exfoliate the skin without the thermal damage associated with light-based machines. This article presents a new variation of a trusted method, using a series of low-strength trichloroacetic acid peels and proper skin preparation that is cost-effective and produces excellent results in selected patients.

For centuries, man has searched for a miracle potion that would reverse aging wrinkled skin. In the early and middle 1900s, various peeling agents were used. After Baker, Gordon, Litton, and others popularized the classic phenol peel in the 1960s, the deep chemical peels became a key procedure in the treatment of the aging face and represented an important component of a successful facial aesthetic practice. Since that time, there has been continued interest in resurfacing the facial skin and an evolution of peeling agents, including those for superficial peeling.

Lasers became popular tools to resurface the skin beginning in the 1990s. While some lasers treat more superficially, others, such as the carbon dioxide lasers, have the potential to treat deeply. The side effects of deep carbon dioxide lasers, such as long-term hypopigmentation, fostered the development of fractionated beams that were designed to lessen tissue damage and reduce such side effects. However, the separation of beams to spare segments of untreated tissue and the reduction of intensity of the fractionated light beam reduce aesthetic results. The cost of laser skin resurfacing can be quite significant. This includes not only the cost of the laser unit but also associated equipment such as smoke evacuators, cooling machines, appropriate safety items such as eyewear and masks, and regular maintenance for the equipment.

Properly structured skin care/peeling protocols using the sequential application of the authors’ superficial chemical peeling technique may approximate many of the fractionated laser treatments. Because of the inexpensive nature of peels, they can be offered as an effective alternative to fractionated laser treatments. This article describes a new variation on a classic technique that can provide greater improvements than those typically obtained by superficial peels. The authors’ technique of enhanced superficial chemical peels has been found to produce excellent results with minimal down time and costs.

Background of chemical peels for facial rejuvenation

As people age, the skin regeneration process slows; the epidermis thins, and the outer stratum corneum layer becomes less organized. The rete pegs and dermal papillae become less pronounced, resulting in a flattening of the dermal–epidermal junction. The dermis also thins, and the collagen and elastin fibers diminish in volume and organization. The additive effects of this aging process and associated solar damage lead to characteristic findings, which include irregular, wrinkled skin with keratosis and pigment changes. These changes are well-addressed with the enhanced superficial chemical peels technique.

Chemical peeling involves the application of a chemical exfoliant that initiates a controlled wound to the epidermis and/or dermis. In general, results are dependent upon the depth of penetration. Penetration can be altered by the type of agent, the concentration of the agent, the time of contact with the skin, the potential reapplication of the agent, and the resistance of the skin. Peeling may be enhanced by pretreating the skin with an effective daily exfoliation program designed to disrupt a damaged keratin surface, allowing improved penetration of the peel, while also prestimulating the basal layer to increase the cellular regenerative capacity. Pretreating is imperative to enhance low-concentration peel formulas. Effective peeling may improve surface irregularities and stimulate fibroblast activity and collagen production.

Superficial peeling agents include alpha hydroxyl acids (glycolic acid, lactic acid, pyruvic acid), salicylic acid, retinoic acid, resorcinol, and trichloracetic acid (TCA, in lower concentrations). Solutions such as Jessner solution (resorcinol, 14 g; salicylic acid, 14 g; lactic acid, 14 mL; ethanol, 100 mL) have also been formulated to peel at a superficial level.

Most superficial peels are used to improve very fine wrinkles and pigmentary changes. However, some peels are used for other indications. The lipophilic nature and anti-inflammatory properties of salicylic acid make this a popular peel for acne-prone patients.

In the past, the concentration of some peels was thought to primarily determine whether it was considered superficial or medium. To a great extent that may be true. For example, TCA used in higher concentrations may be considered a medium-depth peel. However, the authors consider TCA peeling above 35% to be relatively unpredictable, and it is known to be associated with scarring when used above 45%. The time of application can also determine if a treatment is superficial or medium. Repeated single procedure placement of high concentrations of pyruvic acid or glycolic acid, for example, may cause a medium-depth treatment.

Many of the so-called superficial peels may disrupt the stratum corneum, but have limited impact on more advanced skin aging changes. Some of the more aggressive superficial peels (for instance the higher concentrations of glycolic acid) may be an appropriate option for improving overall skin quality, such as rough texture, and some solar damage. Photoaging to a Glogau 1 or 2 level responds well to some types of superficial chemical peeling ( Table 1 ).

Table 1

Glogau classification of photoaging

1–Mild	2–Moderate	3–Advanced	4–Severe
No keratoses	Early actinic keratoses	Moderate actinic keratoses/telangiectasias	Skin cancer/extensive actinic changes
Little wrinkling	Early wrinkling	Wrinkling at rest	Wrinkling and laxity
Little scarring	Mild acne scarring	Moderate acne scarring	Severe acne scarring
Typical age 28–35	Typical age 35–50	Typical age 50–65	Typical age 65+

Acne may sometimes be improved with superficial chemical peels. Superficial pigmentary dyschromias such as solar lentigenes and melasma can also be treated. However, deeper vascular abnormalities may not be addressed.

Although it has been taught that multiple superficial peels are not equivalent to medium or deep peels, it is the authors’ experience that a sequential application of enhanced superficial chemical peels can be effective in reducing fine rhytids when combined with a proper skin care regimen before and after peeling. With adequate skin pretreatment and a series of more aggressive peels that are applied to the proper frosting level, enhanced improvement is attainable using a lower level of TCA. It is the authors’ opinion that the immediate reapplication of the peel can increase the depth of treatment and improve a significant portion of superficial rhytids when used with this protocol.

Technique for chemical peel

The author’s protocol of enhanced superficial chemical peeling is based upon aggressive skin pretreatment, a series of treatments, and peels reaching an enhanced frosting level. The depth of penetration depends on skin cleansing, skin preparation, the concentration used, and the technique of application. The authors’ prepeeling skin preparation and modified TCA application enhance the impact of the weaker TCA concentrations while avoiding the unpredictability of using higher concentrations as well as the thermal tissue damage associated with laser treatments. The peeling can be easily blended in various regions of the face and tailored to regional skin requirements.

The authors’ pretreatment program requires a minimum of 2 weeks of aggressive skin preparation with exfoliation, hydration, and protection. Sunscreens and a strong glycolic acid-based exfoliator are used. Tretinoin is added in many cases of thick, oily, or resistant skin. Hydroquinone is added to the pretreatment regimen when faced with pigmentation considerations. Both in the pretreatment and post-treatment periods, patients should comply with limitations in sun exposure and the daily use of sunscreen. Sunscreen with an SPF factor of 30 or greater is preferred and reduces the incidence of hyperpigmention or repigmentation of dyschromias. Excellent improvements can be seen with an aggressive skin care regimen alone ( Figs. 1 and 2 ).

Antivirals may be recommended as prophylaxis for superficial–medium peel patients with a positive history of herpetic outbreaks. If indicated, antivirals are started the day of or 1 day before the procedure and are continued for 1 to 2 weeks after treatment. The authors do not routinely recommend prophylactic antibiotic therapy for these procedures.

Prepeeling skin preparation includes the daily use of a facial exfoliation cream that contains an effective concentration of glycolic acid for 2 weeks before the procedure. The cream is usually stopped 2 days before the procedure. Glycolic acid is an alpha-hydroxy acid derived from sugar cane that initiates keratinocyte dyscohesion and increases type 1 collagen and hyaluronic acid deposition in the skin. The tightening properties of collagen and the hydrophilic properties of hyaluronic acid give the skin a fuller and less wrinkled appearance.

Tretinoin (eg, Retin A) not only thins the stratum corneum in thick-skinned individuals but also helps prepare the skin for chemical peels by activating dermal fibroblasts and stimulating increased collagen deposition. This product is also used for 2 weeks before the enhanced superficial chemical peel in nonsensitive skin.

Hydroquinone is recommended in patients with significant pigmentation, spotty hyperpigmentation, and melasma. Hydroquinone blocks the production of melanin precursors and subsequently epidermal neo-pigmentation during the healing phase by inhibiting the enzyme, tyrosinase. 4% hydroquinone cream is usually recommended for those patients with Fitzpatrick type 3 skin or greater or for those patients with pigmentary dyschromias. If indicated, this product is used for 2 weeks before the enhanced superficial chemical peels and then resumed for a short period of time after healing.

The depth of the peel depends on the proper skin preparation, concentration of the agent, application duration, and number of applications. The authors prefer peels at 15%, 20%, and 25% TCA. It is the experience of the senior author (PRL) that TCA peeling concentrations greater than 35% are more unpredictable. Although higher concentrations of TCA have been safely used by others, the authors find that lower concentrations can accomplish equivalent benefits without the increased unpredictability of the higher concentrations. The authors increase the depth of their treatment program by the proper 14 day skin pretreatment, immediate pretreatment cleansing, and increasing TCA contact time or reapplication of the TCA until the proper frosting has occurred. Frosting is carried to at least level 2, which is a white frosting with erythema showing through ( Fig. 3 ). A series of 6 to 8 peels performed every 6 to 8 weeks can produce excellent results, but some patients may experience significant improvement with as few as 3 to 4 peel sessions when combined with a diligent skin care regimen ( Figs. 4 and 5 ).