Chemical Peels

Frankie G. Rholdon, MD

Chapter Highlights

Chemical peels are traditionally categorized as being superficial (epidermal), medium-depth (papillary dermis), and deep (reticular dermis).
Selection of the type of chemical peel depends upon the patient’s expectations, desired outcome, and downtime available.
Pretreatment with a topical retinoid can assure even penetration of the peeling agent.
Care should be taken during the treatment to prevent ocular injury, such as the use of petrolatum at the medium and lateral canthi, avoiding the passing of peeling solutions over the patient, and by having eyewash solution readily available at all times during the procedure.
Common superficial chemical peels include glycolic acid, salicylic acid, and Jessner solution.
Common medium-depth chemical peels combine 35% trichloroacetic acid with either Jessner solution, 70% glycolic acid, or solid carbon dioxide.
Phenol peels are the most common deep chemical peels.

Chemical peeling (chemoexfoliation) is the application of a chemical agent to the skin to cause controlled destruction of portions of the epidermis and possibly dermis. This results in exfoliation and removal of superficial lesions, as well as regeneration and remodeling of epidermal and dermal tissues. Chemical peeling to improve aesthetics has evolved throughout history, beginning with the ancient Egyptians using animal oils, salt, alabaster, and sour milk. The active ingredient in sour milk is lactic acid, an alpha hydroxy acid, which is still used in chemical peeling today. Dermatologists have been utilizing modern peeling techniques since the late 1800s. Large advances came with P.G. Unna’s descriptions of salicylic acid (SA), resorcinol, phenol, and trichloroacetic acid (TCA) in 1882. Deep chemical peeling was refined in the 1960s and 1970s by Drs Thomas Baker and Harold Gordon using a saponated formula of phenol and croton oil. Medium-depth chemical peeling was pioneered by Drs Harold Brody, Gary Monheit, and William Coleman in the 1980s.¹ These peeling techniques have
been optimized, and many commercially available proprietary formulations are now available. Dermatologists performed 434,000 chemical peel procedures in 2017,² compared to 425,000 in 2016.³ Society’s desire for a more youthful appearance is driving an increase in the demand for chemical peeling.

The goal of chemical peeling is to remove a uniform thickness of skin to eliminate damaged or unwanted cells and to stimulate rejuvenation through wound healing. Caustic agents used in chemical peeling cause exfoliation through keratocoagulation, denaturation of proteins, and/or disruption of intercellular adhesion. Removal of the epidermis improves pigmentation and texture and destroys unwanted epidermal growths. The wounding also causes the release of pro-inflammatory cytokines and chemokines, activating the inflammatory cascade. This targeted inflammation stimulates neocollagenesis and neoelastinogenesis, reorganization of dermal connective tissue, and regeneration of keratinocytes. This results in epidermal and dermal thickening which can improve the clinical appearance of rhytides and acne scarring. The depth of tissue injury correlates with the amount of tissue remodeling and therefore chemical peels are traditionally categorized by depth of wounding into superficial, medium, and deep chemical peels (Table 5.1).

Superficial chemical peels involve injury to varying levels of the epidermis. Medium-depth peels penetrate the full thickness of epidermis and into the papillary dermis. Deep chemical peels wound into the reticular dermis. The depth of a chemical peel can be influenced by several factors including the type of chemical used, chemical concentration, mode of application, number of applications, and amount of time the chemical is active on the skin. The depth of injury directly correlates with healing time, risk of complication, and cosmetic outcome.

PREOPERATIVE (TABLE 5.2)

History/Physical Examination

Patient consultation is vital to a successful procedure and should begin by assessing the patient’s goals and motivation. There are several patient factors that will impact the success of the treatment, including unrealistic expectations, inability to tolerate the procedure or accommodate downtime, and inability to avoid the sun. A targeted medical history should include pregnancy and breastfeeding status, any previous facial resurfacing procedures, smoking status, recent facial surgeries, previous radiation in the treatment area, history of abnormal scar formation or pigmentation, isotretinoin therapy in the previous 6 months, and history of hepatic, renal, or cardiac disease (relative to deep peeling only). Physical exam involves evaluation of areas of patient concern, degree of photoaging, Fitzpatrick skin type (Table 5.3), as well as identifying any contraindications such as active infection, uncontrolled dermatitis, open wounds, or abnormal scars.

Counseling

Proper patient counseling is essential in both outcome and patient satisfaction (Table 5.4). Patient goals and expectations should be communicated and aligned with the chosen procedure. The provider should ensure that the patient understands the expected outcome and limitations of the treatment. Detailed information regarding the preparation required prior to the procedure, as well as the procedure technique,

expected discomfort, anticipated downtime, aftercare protocol, and potential complications, must be reviewed with the patient in detail. The patient should understand normal healing and be educated on potential adverse events to enable early identification and intervention in the case of complications. After the patient is educated and given the opportunity to ask questions, written documentation of informed consent is obtained.

TABLE 5.1 Chemical Peel Types

	Superficial Peel	Medium-Depth Peel	Deep Peel
Depth of injury	Epidermis	Papillary to upper reticular dermis	Mid reticular dermis
Indications	Pigmentation abnormalities Acne Undesirable superficial skin texture (not including rhytides or scarring)	Pigmentation abnormalities Superficial rhytides Superficial scarring Superficial epidermal growths	Pigmentation abnormalities Superficial to deep rhytides Scarring Superficial epidermal growths
Contraindications	Active infection Open wounds Uncontrolled dermatitis History of abnormal scarring Unrealistic patient expectations Inability of the patient to tolerate the procedure and recovery Patient inability to avoid sun exposure	Active infection Open wounds Uncontrolled dermatitis History of abnormal scarring Unrealistic patient expectations Inability of the patient to tolerate the procedure and recovery Patient inability to avoid sun exposure Previous, recent (<6 mo) facial undermining surgery in the treatment area Isotretinoin in the previous 6 mo History of facial radiation in the treatment area Smoking (may interfere with healing) Fitzpatrick skin types IV-VI	Active infection Open wounds Uncontrolled dermatitis History of abnormal scarring Unrealistic patient expectations Inability of the patient to tolerate the procedure and recovery Patient inability to avoid sun exposure Previous, recent (<6 mo) facial undermining surgery in the treatment area Isotretinoin in the previous 6 mo History of facial radiation in the treatment area Smoking (may interfere with healing) Fitzpatrick skin types IV-VI History of cardiac or hepatorenal disease if application is more than one cosmetic unit
Agents	Salicylic acid Glycolic acid Jessner solution Tretinoin Glycolic acid Lactic acid TCA 10%-35% Mandelic acid Pyruvic acid Others	TCA 50% as single frost Solid CO₂ followed by 35% TCA Jessner solution followed by 35% TCA Glycolic acid solutions applied and washed off, followed by 35% TCA Full strength phenol, USP 88%	Phenol-croton oil peels
Complications	Post inflammatory pigment alteration Prolonged erythema Infection (bacterial, fungal, viral) Reactivation of HSV Allergic reaction Increased skin sensitivity	Post inflammatory pigment alteration Prolonged erythema Infection (bacterial, fungal, viral) Reactivation of HSV Allergic reaction Increased skin sensitivity Acneiform eruption Milia formation Scarring	Post inflammatory pigment alteration Prolonged erythema Infection (bacterial, fungal, viral) Reactivation of HSV Allergic reaction Increased skin sensitivity Acneiform eruption Milia formation Scarring Cardiotoxicity/arrhythmia (due to systemic absorption of phenol) Hepatotoxicity Nephrotoxicity

TABLE 5.2 Preoperative

History.
1. History of abnormal scar formation, including keloids.
2. Pregnant or lactating.
3. Previous facial surgical procedures, dermabrasion, or chemical peels.
4. Tobacco use.
5. Previous radiation exposure.
6. Determine patient’s subjective areas of concern, goals, and exceptions.
Physical exam.
1. Fitzpatrick skin type (Table 5.3).
2. Assess degree of photoaging and goals of treatment to determine chemical peel type.
3. Presence of active infection (especially HSV).
Prescribe antiviral prophylaxis (if indicated).
Prepare the skin with tretinoin and sun protection prior to the scheduled procedure.
Obtain patient consent.
Take patient photographs.
Hyperkeratotic lesions may be removed prior to chemical peeling.
Cleanse and degrease the face appropriately using cleansers, acetone, alcohol, or a combination.
Ensure proper eyewash equipment is readily accessible in case of accidental ocular exposure of peeling solution.

TABLE 5.3 Fitzpatrick Skin Types

I	Always burns, never tans
II	Always burns, tans minimally
III	Burns moderately, tans gradually
IV	Burns minimally, always tans uniformly
V	Rarely burns, tans easily
VI	Never burns, deeply pigmented

TABLE 5.4 Medium-Depth Chemical Peel Patient Instructions

Pretreatment instructions:

You should not have this treatment if you are pregnant or if you have taken isotretinoin (Accutane) within the previous 6 mo.
Discontinue topical retinoids or retinol 1 d prior to the treatment.
Avoid excessive sun exposure at least 2 wk prior to the procedure.
Avoid microdermabrasion, waxing, aggressive exfoliation, or any other treatments that may be irritating to the skin for at least 1 wk prior to the procedure.
Your provider may recommend antiviral medication prior to the treatment to help prevent fever blisters from occurring after the procedure. If so, take as instructed.

What to expect during your treatment:

Arrive with the treatment area clean, free of makeup and lotions and clean shaven.
A medical staff member will take photographs prior to your treatment to track the results.
The skin will be prepped for the chemical peel with alcohol and acetone.
The physician will rub the skin with solid CO₂ (dry ice). This is cold and can sting in some areas.
As the peeling solution is applied to the skin, you may experience tingling, a heat sensation, stinging or burning. This is temporary and will last about 5-10 min.
Cold compresses will then be applied to cool the skin and provide comfort.
A soothing ointment will then be applied to the skin.
Your skin will appear white with an underlying pink/red coloration. The white color will fade in 1-2 h.

Posttreatment instructions:

After 24 h, cleanse the face with a gentle facial cleanser twice daily. Avoid scrubbing.
Apply a thin layer of white petrolatum immediately after cleansing the face. Reapply as needed for itchy, tight skin.
Facial swelling will occur on post peel days 1-4. The swelling will be worse in the morning and improve throughout the day.
Peeling will begin on day 3 or 4 and continue until day 9 or 10.
Avoid scrubbing, picking, or peeling the skin during the healing process.
Avoid sun exposure during the healing process. Once the peeling is completed, wear sunscreen daily and protect from sun for at least 6 mo.
Once the peeling is complete and the skin no longer feels sensitive, resume skin care regimen as instructed by physician.
You should not have pain, worsening redness, or oozing during this process. If these occur, call the office.

Preprocedure Treatment

To ensure optimal outcomes, a pretreatment skin care regimen is recommended for at least 4 weeks prior to the chemical peel. Patient compliance with the pretreatment regimen primes the skin for uniform penetration of the peeling agent, reduces healing time, ensures tolerability and compliance to topical agents, and decreases the risk of complications. Any infection, dermatitis, or inflammation of the skin within the treatment area should be addressed and treated appropriately. The patient should be advised to aggressively photoprotect the treatment area with daily application of broad-spectrum sunscreen and sun protective behaviors (UV protective clothing, hats, avoidance of excessive sun, etc.). It is not recommended to have facial hair in the treatment area; the patient should be instructed to shave the area 12 to 24 hours prior to the scheduled procedure if necessary. The patient should also be instructed to arrive on the day of the procedure with clean skin and not wearing contact lenses.

Topical vitamin A preparations are recommended prior to the planned procedure. Retinoids act on the upper papillary dermis by increasing type I collagen production and decreasing collagen destruction by matrix metalloproteinases. They have also been shown to efface rhytides through epidermal hyperplasia, compaction of the stratum corneum, and thickening of the granular cell layer of the epidermis.⁴ Tretinoin, or all-trans-retinoic-acid, is a first-generation naturally occurring retinoid and is the most extensively studied in aesthetic medicine. The preoperative use of topical tretinoin decreases healing time after a chemical peel.⁵ It is recommended to apply tretinoin cream 0.05% or 0.1% daily for 4 weeks prior to chemical peeling and discontinue use 24 hours before the scheduled procedure. Although not studied prior to chemical peeling, tazarotene is a synthetic retinoid that has shown to improve the cosmetic appearance of photoaging. Tazarotene 0.05% cream was shown to be equivalent to tretinoin 0.05% cream in the treatment of the mottled hyperpigmentation and fine rhytides of photodamaged skin.⁶ In the case of retinoid sensitivity, patients may use topical adapalene. Adapalene is a synthetic third-generation retinoid with a lower incidence of retinoid dermatitis. Although studies comparing tretinoin to retinol are lacking, it is generally believed that retinols are not as clinically effective antiaging products as prescription retinoids.

Pigmentation is a common indication for chemical peeling. Topical preparations are frequently used to decrease skin pigmentation both before and after chemical peeling. Hydroquinone, the most commonly used agent, decreases pigment production through the inhibition of tyrosinase, the rate limiting enzyme in melanin synthesis. Although research involving the use of topical hydroquinone prior to chemical peels is insufficient, it is commonly used when pigmentation is the indication for chemical peeling.

Reactivation of the herpes simplex virus (HSV) is a known complication of chemical peeling. Herpetic infections following chemical peeling lead to increased morbidity, delayed reepithelialization, and scarring. This risk of reactivation correlates with the depth of wounding. It is recommended to assess the patient’s history of orolabial herpes preoperatively. In superficial peeling, pretreatment with antiviral prophylaxis is optional and should be considered in patients with a history of recurrent HSV outbreaks. Prophylactic antiviral therapy should be initiated prior to all medium and deep chemical peel procedures, regardless of patient history. Valacyclovir at a dose of 500 mg twice daily beginning the morning of the procedure was found to be an effective prophylaxis against HSV reactivation.⁷ In the study, the treatment was continued for 14 days, but it is generally believed safe to discontinue once reepithelialization is complete.

Isotretinoin (13-cis-retinoic acid) is a metabolite of vitamin A that is FDA-approved for the treatment of severe and nodulocystic acne. The package insert advises against performing cosmetic procedures, including chemical peels, within 6 months of therapy
due to risk of scarring.⁸ These recommendations were based on sporadic adverse events. A systematic review of the literature provided a consensus recommendation that there is insufficient evidence to recommend delaying superficial chemicals in patients treated with isotretinoin.⁹ The American Society for Dermatologic Surgery Guidelines Task Force released consensus recommendations regarding the safety of cosmetic procedures after isotretinoin use in 2017, stating that “superficial peels can be safely administered to patients taking isotretinoin within 6 months after isotretinoin therapy.” There was no recommendation on the use of medium or deep chemical peeling due to insufficient data.¹⁰ It is therefore recommended to delay medium and deep-depth chemical peeling to at least 6 months after isotretinoin therapy.

Botulinum toxin type A is available as an injection for the treatment of dynamic facial rhytides, with well-established safety and efficacy. Pretreatment of glabellar, forehead, and periocular rhytides with botulinum toxin should be considered prior to chemical peeling. This is not only an adjuvant treatment of facial rhytides, but also may improve the cosmetic outcome of the subsequent chemical peel. A key factor in scar formation is the tension that acts on the wound during the healing phase. By blocking acetylcholine neurotransmitter release at the neuromuscular junction, botulinum toxin inhibits muscle tension at the site of the healing wound. Botulinum toxin pretreatment has shown to improve the cosmetic appearance of scar formation following surgical procedures on the face and neck¹¹ as well as improve the hyperdynamic facial lines following laser resurfacing.¹² If rhytid improvement is a goal of the chemical peel, pretreatment with botulinum toxin should be discussed with the patient in the preoperative period.

Superficial and medium-depth peels are generally tolerable and do not require anesthesia. The patient should be evaluated prior to the procedure regarding anxiety and pain tolerance. For chemical peels with more discomfort, such as the medium-depth peels and higher concentration TCA peels, an anxiolytic medication given 30 minutes prior to the procedure is optional. If this medication is prescribed, the patient should not drive to or from the procedure.

Photographic Documentation

The treatment area should be photographed prior to the chemical peel procedure. Ensure that the area is clean and free of makeup. Distractions should be minimized; therefore, it is recommended to use a headband to position hair away from the face and to remove jewelry. Photos should be standardized using consistent positioning and lighting. The photographs are part of the medical record, require Health Insurance Portability and Accountability Act (HIPAA)-compliant storage, and should be used for patient care as part of the medical record. If identifiable photographs are to be used for publications or advertising, written patient consent is necessary.

OPERATIVE (TABLE 5.5)

Prior to beginning the chemical peel, all necessary supplies (Table 5.6) should be present and readily accessible. Care should be taken to ensure that the correct chemical peeling agent and concentration were selected and labeled accurately. The patients should wash their face with a gentle skin cleanser and position hair away from the treatment area using a headband or cap. For facial peeling, position the patient reclined at 30° to 45° angle with eyes closed. Alcohol and/or acetone on a gauze are used to clean and degrease the treatment area. A fan can be helpful to protect the patient from the noxious fumes.

TABLE 5.5 Operative (Superficial and Medium-Depth Peels)

Patient preparation.
1. Ensure the treatment area is clean.
2. Position hair away from the treatment area using headband or cap.
3. Position the patient (for facial peeling at 30°-45° angle with eyes closed is recommended).
4. Ensure an eyewash bottle of normal saline is readily accessible.
Clean and degrease the skin with alcohol and/or acetone on a gauze.
Protect any areas of concern with petroleum jelly as needed.
Check the solution labeling to ensure correct agent and concentration prior to transfer into the small glass container.
Apply the peeling solution.
1. Apply the chemical quickly using appropriate instrument (cotton-tipped applicators, sable brush, gauze).
2. Prevent lines of demarcation with a light application at the border of the treatment area.
3. Number of applications and end points vary by chemical peel.
Termination of the chemoablation (varies by chemical peel).
1. Glycolic acid: neutralizes with dilute sodium bicarbonate solution.
2. Lactic acid.
3. Mandelic acid.
4. Pyruvic acid.
5. TCA is self-neutralizing; however, cool water compresses can be used once depth of ablation is achieved to prevent unwanted deeper injury.
Apply cold compresses for patient comfort.
Apply emollient and physical sunblock.

To avoid accidental spillage, the peeling solution should never be passed over the patient. Special care is taken to avoid drips or spills near the eye area, and the patient’s eyes should remain closed for the procedure. An eyewash bottle of normal saline should be present in the procedure room at all times in case of accidental exposure. It is optional to protect vulnerable areas with the application of white petrolatum. The medial canthus and nasojugal folds can pool peeling solution resulting in deeper than desired wounding. The medial and lateral canthi can also be protected with petrolatum to prevent tears from
interacting with the peeling solution. This can result in premature neutralization of peeling solution or “wicking” of peeling solution into the eyes. Clean gauze or cotton-tipped applicators should also be used to prevent complications from tearing.

TABLE 5.6 Peeling Supplies