Skin type	Color	Reaction to sun
I	Very white or freckled	Always burns
II	White	Usually burns
III	White to olive	Sometimes burns
IV	Brown	Rarely burns
V	Dark brown	Very rarely burns
VI	Black	Never burns

The patient with type I or II skin with significant photodamage needs regular sunscreen protection prior to and after the procedure. The patient, though, has little risk for hypopigmentation, reactive hyperpigmentation or postinflammatory hypopigmentation (PIH) after a chemical peeling procedure. However, a patient with any of the skin types from III to VI has a greater risk for pigmentary dyschromia – hyper or hypopigmentation – after a chemical peel and may need pre and post treatment with both sunscreen and bleaching products to prevent these complications. Pigmentary risks are generally not a great problem with very superficial and superficial chemical peeling but may become a significant problem with medium and deep chemical peels as well as CO₂ or fractional laser resurfacing. It can also be a risk when regional areas such as lips and eyelids are peeled with deep peeling or pulsed CO₂ laser, creating a significant color change in these cosmetic units from the rest of the face. This has been classified as the ‘alabaster look’ that is seen with taped, deep chemical peels in regional areas. This is an objectionable side-effect of deep taped phenol peeling, and to a lesser extent with laser resurfacing, and should be avoided now as patients demand a natural look. Though this was an acceptable look in the 1970s, it is generally not tolerated in the new millennium. The physician must inform patients of this potential problem (especially those with skin types III to VI) for full face deep peels or resurfacing procedures, justifying the benefits of the procedure, outweighing these risks and, in addition, plan for the appropriate techniques to prevent these unwanted changes in color.

• Glogau system

The Glogau system classifies severity of photodamage, taking into account the degree of epidermal and dermal degenerative effects. The categorization is from I to IV, ranging from mild, through moderate and advanced, to severe photodamaged skin. These categories are devised for therapeutic intervention. Type I in young individuals or minimal degree photodamage should be treated with light chemical peeling and medical treatment. Types II and III would entail medium-depth chemical peeling, while type IV would need those modalities listed plus cosmetic surgical intervention for gravitational changes (Box 14.2). Type III or IV can have combination procedures dependent on the degree of damage in each area.

Based on Glogau RG 1994 Chemical peeling and aging skin. Journal of Geriatric Dermatology 2(1):30–35

• Index of photoaging skin

The index of photoaging skin is a system of quantitating photodamage and using numerical scores that would fit into corresponding rejuvenation programs. In analyzing photodamage, the major categories include epidermal color, skin lesions, textural changes, and dermal changes. Photoaging changes include wrinkles, cross-hatched lines, sallow color, leathery appearance, crinkly thin parchment skin, and the pebblish white nodules of milia. Each of these is classified, giving the patient a point score of between one and four. In addition, the number and extent of lesions are categorized from freckles, lentigines, telangiectasias, actinic and seborrheic keratoses, skin cancers, and senile comedones. These are also added in the classification system and the final score results are tabulated. A total score of between one and four indicates very mild damage and the patient would adequately respond to a five-step skin care program including sunscreen protection, retinoic acid, glycolic acid peels and selective lesional removal. A patient scoring between five and nine requires all of the above, plus a repetitive superficial peeling agents program such as glycolic acid, Jessner’s solution or lactic acid peels. A score of 10–14 suggests the inclusion of medium-depth chemical peeling, and if a patient scores 15 or above the practitioner will be including deep peeling or laser resurfacing in the treatment (Figs 14.1 and 14.2). Thus, the patient can understand during the consultation the degree of photodamage and the necessity for an individual peeling program (Table 14.3). The system can also quantitate individual cosmetic units indicating more aggressive resurfacing for the lids and/or lips than surrounding cheeks and forehead.

Figure 14.1 The index of photoaging skin can separate severity of damage and guide the appropriate combination of procedures. Moderate damage is shown in these photographs

Figure 14.2 Severe damage, as determined by using the index of photoaging skin

Table 14.3 Index of photoaging

The chief indications for chemical peeling are associated with the reversal of actinic changes such as photodamage, rhytids, actinic growths, pigmentary dyschromias, and acne scars. The physician thus can use his classification systems to quantitate the level of photodamage and prescribe the appropriate chemical peeling combination.

Types of Combination Chemical Peel

• Superifical chemical peeling

Minimally aggressive procedures are commonly combined with superficial chemical peels to enhance the benefits of these procedures. Light chemical peels commonly used include:

• Trichloroacetic acid 10–20%

• Jessner’s solution

• Glycolic acid 40–70%

• Salicylic acid-betahydroxy acid

• Tretinoin.

Each of these agents has its own characteristics and methodology and a physician must be thoroughly familiar with the chemicals, methods of application, and the nature of healing. The usual time for healing is from 1 to 4 days depending on the chemical and its strength. These agents range from noninflammatory (salicylic acid peels) to moderately inflammatory (Jessner’s solution) and each has a specific purpose (Fig. 14.3).

Figure 14.3 Spectrum of superficial chemical peeling

Cosmeceutical pharmaceutical agents are commonly combined with chemical peels to enhance exfoliative and regenerative effects. Retinoic acid preparations are prescribed as daily home care to accelerate epidermal proliferation, so there is an increase in epidermal thickness despite the stratum corneum being shed. The application of retinoic acid enhances the effectiveness of light and even medium-depth chemical peeling to texture, tone, and smooth the skin. Used in combination with alpha-hydroxy acids (AHAs) retinoic acid prepares the skin for the peel procedure.

Glycolic acid creams, cleansers, and exfoliating preparations are used to boost epidermal exfoliation, reduce stratum corneum thickness and augment the peel penetration, thus enhancing the uniformity of the light chemical peel. Pretreatment is also essential for combination medium-depth peels.

Sunscreens are necessary accompaniments to all peeling procedures and the patient should begin this prior to the peel. The proper FDA approved sunscreen should be chosen based on the patient’s skin type and procedure chosen. The choices are UVA filters, UVB filters and inorganic sunscreens (Table 14.4).

Table 14.4 Sunscreens and their photo protection

Screens	UV protection (nm)
UVB
p-Aminobenzoic acid (PABA)	260–315
Salicylates	260–310
Cinnamates	280–310
UVA
Benzophenones	270–350
Meradimate	336
Avobenzone	310–40
Inorganic screens
Titanium dioxide	290–360
Zinc oxide	290–400

When treating pigmentary problems such as melasma, reactive pigmentary dyschromias or treating skin types III–V, the peeling procedure should be accompanied by a topical bleaching product, retinoic acid and a sunscreen. Hydroquinone is a pharmacologic agent that blocks the enzyme tyrosinase from developing melanin precursors for the production of new pigment. Its use will block the production of new pigment as the new epidermis is healing after a chemical peel. Together, this topical combination of hydroquinone, retinoids and sunscreens will enhance the effect of the peel for pigmentary problems. Pretreatment should be instituted six weeks prior to the peel procedure for maximal benefit.

The peeling agent of choice to use for light pigmentary problems is salicylic acid, 20 or 30%. It is noninflammatory, reducing the potential for reactive postinflammatory hyperpigmentation. This is a repetitive procedure that usually takes three to six treatment sessions over 4 to 6 months. Other adjunctive procedures that will supplement peeling and cosmeceuticals for pigmentary problems include microdermabrasion to enhance exfoliation and selective lasers such as intense pulsed light, 532 nm, diode and Q-switch yttrium-aluminum-garnet (YAG).

Light chemical peeling for photoaging changes utilizes the more inflammatory agents such as Jessner’s solution, glycolic acid and TCA (Fig. 14.4). These procedures can all be combined with cosmeceutical agents and even exfoliative procedures such as microdermabrasion. It is also combined with intense pulsed light, photomodulation and selective lasers. The peels will produce epidermal sloughing of various degrees and thus should not be performed on the same day as the other procedures. Separating them by alternating weeks of treatment will allow enough recovery for the combined procedures to be effective.

Figure 14.4 Five 15% TCA peels repeated over 2 months – before (A) and after (B)

TCA has been the most versatile of all peeling agents and has been used in concentrations weight-per-volume from 15% to 50%. As concentration increases, ablative injury is greater as well as rejuvenative effects for photoaging skin. In most patients, TCA in concentrations above 25–30% affects the dermis as well as epidermis, having the effect of medium and deeper chemical peels (Fig. 14.5).

Figure 14.5 TCA frosting – protein precipitation

• Medium-depth chemical peeling

Medium-depth peels consist of controlled damage through the epidermis and papillary dermis, with variable extension to the upper reticular dermis. Both medium-depth and deep chemical peeling produce epidermal necrosis, papillary dermal edema and homogenization, and a sparse lymphocytic infiltrate within the first several days. During the following 3 months postoperatively, there is increased collagen production with expansion of the papillary dermis and the development of a mid-dermal band of thick, elastic-staining fibers. These changes correlate with continued clinical improvement in texture and smoothness during this time.

For many years, 40 to 60% TCA was the prototypical medium-depth peeling agent because of its ability to ameliorate fine wrinkles, actinic changes, and preneoplasia. TCA as a single agent for medium-depth peeling has fallen out of favor because of the high risk of complications, especially scarring and pigmentary alterations, when used in strengths approaching 50% and higher. Today, most medium-depth chemical peels are combination peels performed utilizing 35% TCA in combination with either Jessner’s solution, 70% glycolic acid, or solid carbon dioxide (CO₂) as a ‘priming’ agent (Table 14.5). These combination peels have been found to be as effective as 50% TCA alone but with fewer risks. The level of penetration is more easily controlled with these combination peels, thereby preventing the ‘hot spots’ that can produce the dyschromias and scarring seen with higher concentrations of TCA.

Table 14.5 Agents used for medium-depth chemical peeling

Agent	Comment
40–50% Trichloroacetic acid (TCA)	Not recommended
Combination 35% TCA–solid CO₂ (Brody)	The most potent combination
Combination 35% TCA–Jessner’s (Monheit)	The most popular combination
Combination 35% TCA–70% glycolic acid (Coleman)	An effective combination
88% phenol	Rarely used

Brody developed the use of solid CO₂ to freeze the skin prior to the application of 35% TCA. This causes complete epidermal necrosis and significant dermal edema, thereby allowing deeper penetration of the TCA in selected areas. This technique is particularly useful to efface the edges of mild acne scars and to destroy thicker epidermal growths. The author then described a combination medium-depth peel in which Jessner’s solution is applied, followed by 35% TCA. Similarly, Coleman and Futrell have demonstrated the use of 70% glycolic acid prior to the application of 35% TCA for medium-depth peeling. The Jessner’s solution and glycolic acid both appear to effectively weaken the epidermal barrier and allow deeper, more uniform, and more controlled penetration of the 35% TCA.

Current indications for combination medium-depth chemical peeling include Glogau type II photoaging, epidermal lesions such as actinic keratoses, pigmentary dyschromias, and mild acne scarring, and also to blend the effects of deeper resurfacing procedures.

The Jessner’s–TCA Peel

The Jessner’s–35% TCA peel is particularly useful for the improvement of mild to moderate photoaging (Fig. 14.6A). It freshens sallow, atrophic skin and softens fine rhytids, with minimal risk of textural or pigmentary complications. Collagen remodeling occurs for as long as 3 to 4 months postoperatively, during which there is continued improvement in texture and fine rhytides. Deep furrows, however, are not eliminated with this peel. When used in conjunction with a retinoid, bleaching agent, and sunscreens, a single Jessner’s–35% TCA peel lessens pigmentary dyschromias and lentigines more effectively than repetitive superficial peels (Fig. 14.7). Epidermal growths such as actinic keratoses also respond well to this peel. In fact, the Jessner’s–35% TCA peel has been found to be as effective as topical 5-fluorouracil chemotherapy in removing both grossly visible and clinically undetectable actinic keratoses but has the added advantages of lower morbidity and greater improvement in associated photoaging (Fig. 14.8).

Figure 14.6 (A) Combination procedure utilizing perioral–periorbital CO₂ laser resurfacing with Jessner’s + 35% TCA peel over remaining face. The peel will blend color and texture of the laser treated areas. Preoperative: the eyelids and lips need deeper resurfacing than cheeks, which require only medium depth injury. (B–F) Combinations: laser resurfacing to eyelids, perioral area; medium-depth peel to face, light peel to neck. Preoperative; the peel is performed first; postoperative laser and peel; postoperative 4 day; postoperative 4 months

Figure 14.7 Monheit combination peel. (A) Preoperative; (B) postoperative

Figure 14.8 Medium depth chemical peel for treatment of diffuse actinic keratoses and photoaging. Jessner’s + 35% TCA was used as a single treatment with healing in 8 days. (A) Preoperative: the white spots represent prior cryosurgical treatment; (B) frosting after TCA – skip areas need retreatment as these represent thicker growths of stratum corneum; (C) postoperative – 1 month

The Jessner’s–35% TCA peel is effective in combination to blend the effects of other resurfacing procedures with the surrounding skin. Patients who undergo laser resurfacing, deep chemical peeling or dermabrasion to a localized area such as the periorbital or perioral region often develop a sharp line of demarcation between the treated and untreated skin. The treated skin may appear hypopigmented (also known as pseudohypopigmentation) in comparison to the untreated skin. These irregularities are often conspicuous and are troubling to the patient. A Jessner’s–35% TCA peel performed on the adjacent untreated skin helps to blend the area treated with deep resurfacing with its surroundings. For example, a patient with advanced photoaging in the periorbital region and moderate photoaging on the remaining face may desire CO₂ laser resurfacing only around the eyes. In this patient, medium-depth chemical peeling of the areas not treated with the laser would improve the photoaging in these regions and avoid a line of demarcation (see Fig. 14.6B–F). Similarly, a patient having spot dermabrasion to a localized scar would benefit from a Jessner’s–35% TCA peel to the remainder of that cosmetic unit or to the rest of the face. It is important to note that when used in combination with other resurfacing procedures such as laser resurfacing or dermabrasion, the peel should be performed first in order to avoid accidental application of the peeling agent onto previously abraded areas of skin.

The combination Jessner’s–35% TCA peel should be a part of the patient’s full rejuvenation program. This should include botulinum toxin to relax glabellar, forehead and perioral wrinkles, soft tissue filling agents such as hyaluronic acid to fill deep grooves and augment areas of facial atrophy. In addition, selective lasers are used to treat vascular lesions such as telangiectasias and hemangiomas that do not respond to peel alone. These auxillary procedures should be performed at least one week prior to the peel so that there is no interference with the healing process.

• Deep chemical peeling

Deep resurfacing is defined as tissue injury to the upper reticular dermis. This can be accomplished with the Baker-Gordon peel, CO₂ resurfacing laser or dermabrasion.

Patients with Glogau types III and IV may require deep chemical peeling, motorized dermabrasion, or laser resurfacing to improve their greater degree of skin damage. As discussed with medium-depth peels, deep chemical peeling leads to production of new collagen and ground substance down to a level in proportion with the depth of the peel. Deep peels create an injury through the papillary dermis, into the upper reticular dermis, and may extend into the mid-reticular dermis. Deep peeling entails the use of either TCA in concentrations above 50% or a phenol-containing preparation. Because of the risk of scarring and other complications with such potent concentrations of TCA, this agent is not recommended for deep chemical peeling. Therefore, solutions containing phenol remain the agents of choice for deep chemical peels.

Phenol Peeling

The application of pure, undiluted, 88% phenol to the skin causes rapid and complete coagulation of epidermal keratin proteins and is thought to block itself from further penetration. Classified as a medium-depth peeling agent, pure phenol is rarely used for chemical peeling because its limited depth of penetration results in a lesser degree of effectiveness. In contrast, the Baker-Gordon peel utilizes phenol in a formulation that permits deeper penetration into the dermis than full-strength phenol. First described in 1961, the Baker-Gordon peel has been used successfully for many years and the formula consists of Septisol (Vestal Laboratories, St. Louis, MO), croton oil, and tap water added to a solution of phenol, reducing its concentration to 50 or 55% (Table 14.6). The mixture of ingredients is freshly prepared and must be stirred vigorously prior to application, owing to its poor miscibility. The liquid soap, Septisol, is a surfactant that reduces skin tension, allowing a more even penetration. Croton oil is a vesicant epidermolytic agent that enhances phenol absorption. Recent investigations into the effects of this peel using varying concentrations of both phenol and croton oil have suggested that the procedure’s efficacy is more related to the amount of croton oil than the concentration of phenol. Modifications of the original Baker-Gordon formula in order to improve the risk to benefit ratio of deep peeling are discussed in depth in Chapter 8.

Table 14.6 The Baker-Gordon formula

88% liquid phenol, USP (BP)	3 mL
Tap water	2 mL
Septisol liquid soap	8 drops
Croton oil	3 drops

There are two main variations in deep chemical peeling with the Baker-Gordon phenol formula: occluded and unoccluded. Occlusion of the peeling solution with tape is thought to increase its penetration and extend the injury into the mid-reticular dermis. This technique is particularly helpful for deeply lined, ‘weather-beaten’ faces but should be utilized only by experienced surgeons because of the higher risk of complications. The unoccluded technique, as modified by McCollough, involves more abrasive cleansing of the skin and the application of multiple coats of peel solution in one sitting. This may enhance the efficacy of the solution but without penetrating as deeply as in an occluded peel. In the hands of a skilled and knowledgeable surgeon, both methods are safe and reliable in rejuvenating advanced to severe photoaged skin.

As one evaluates cosmetic units, the deep resurfacing technique (Baker-Gordon peel or CO₂ resurfacing) may be indicated only for the periorbital and perioral sites. The combination Jessner’s TCA peel is then used on the remaining face as a less aggressive procedure. This greatly decreases the danger of a phenol peel as less surface area is affected lowering the serum level of phenol and its systemic toxicity. The procedure can be performed with local blocks to the deep resurfacing areas with less overall discomfort and a quicker recovery.

Combining Levels of Peel and Other Procedures

Deep chemical peeling can significantly improve or even eliminate deep furrows as well as other textural and pigmentary irregularities associated with severe photoaging (Fig. 14.9). A remarkable degree of improvement is the expected result of deep chemical peeling when performed properly on carefully selected patients. Combining superficial, medium-depth and deep peeling and/or resurfacing procedures will selectively give the cosmetic unit or area of the body the safest and most effective level of resurfacing (Table 14.7).

Figure 14.9 Advanced photoaging of perioral rhytids treated with Baker’s phenol peel. (A) Preoperative demonstrating perioral rhagades, textural and pigmentary changes with epidermal growths; (B) postoperative – 2 years later (note the phenol peel maintains correction for many years)

Table 14.7 Levels of resurfacing

• Combining levels of peel

The use of these peel combinations will enhance a monotherapy procedure. An example would be the patient with moderately severe photoaging changes around the periorbital and perioral areas, such as deep wrinkles and crepey eyelid skin and rhagades around the mouth, combined with only moderate photoaging changes around the rest of the face. This would be characterized by epidermal growths, sallow color, and fine lines. This patient would best be treated by CO₂ laser resurfacing of the perioral and periorbital areas and with the Jessner’s–35% TCA peel around the rest of the face. A light peel such as the Jessner’s peel alone is also performed from the neck down to the shoulders to further blend the unit areas for a natural result (Fig. 14.10).

Figure 14.10 Eyelids and perioral skin for CO2 laser resurfacing. (A) Preoperative; (B) postoperative – the pigmentation below the eye is a shadow only

• Combining peels with other procedures

Chemical peeling	Laser	Dermasanding
Jessner’s + 35% TCA – face	Perioral	Facial borders
Jessner’s alone – neck and chest	Periorbital	Upper 1/3 neck Laser skip areas

Botulinum Toxin and Fillers

Relaxing spasmodic muscle producing dynamic wrinkles with botulinum toxin is an adjunctive procedure that supplements medium peeling or resurfacing procedures (Fig. 14.14). De-innervating muscles causing frown lines, forehead wrinkles, and crow’s feet prior to peeling and resurfacing procedures will produce a better response than peeling or laser alone. This is because the dynamic wrinkles are put to rest and, as new dermal collagen is formed over the ensuing 4 to 6 months, there is minimal muscle movement to wear down the new collagen as the wrinkles are static. The immediate results appear better than with solely laser treatment as the dynamic folds that do not respond to laser or peel alone will improve, as will the fine lines and crepiness that is response to resurfacing. Similarly, botulinum toxin can be used around the lips to put the dynamic perioral lines to rest during the healing phase of the peel.