Medium And Deep Chemical Peels
Gary D. Monheit, M.D.
Associate Professor
Department of Dermatology
University of Alabama at Birmingham
Birmingham, Alabama

The explosion of interest in chemical peeling and laser resurfacing on the part of cosmetic surgeons has paralleled the general public’s interest in acquiring a youthful appearance by rehabilitating the photoaged skin. The public’s interest has been further heightened by advertising for cosmetic agents, over the counter chemicals and treatment programs that have entered the general market of products meant to rejuvenate skin and erase the marks of sun damage and age. Most of these over the counter home do-it-yourself programs have been tried by patients and by the time they consult their dermatologist, plastic surgeon or cosmetic surgeon, they are ready for a more definitive procedure performed with either chemical peeling or laser resurfacing. It is the obligation of the physician to analyze the patient’s skin type and the degree of photoaging skin, and thus prescribe the correct facial rejuvenation procedure. This should be the procedure or combination of procedures that will give the greatest benefit for the least risk factors and morbidity. The cosmetic surgeon should have available for his consumer the options of medical or cosmoceutical topical therapy, dermabrasion, chemical peeling, and lasers available for selective skin destruction and resurfacing. Each of these techniques maintains a place in the armamenteria of the cosmetic surgeon to provide the appropriate treatment for each individual patient and his specific problem.

The approach to photoaging skin has expanded beyond a one-stage procedure to now include preparatory medical therapy and post-treatment cosmoceutical topical therapy to maintain results and prevent further photodamage. Thus, the cosmetic surgeon’s office has become not only the site for a surgical treatment session, but also an educational setting for skin protection and care and a marketplace for the patient to obtain the necessary topicals for skin protection. It is up to the physician to fully understand the nature of skin and sun damage, protective techniques available, and active agents that work as cosmoceutical preparations. Having available multiple procedures to solve these problems will make his patients better candidates for the right procedure to restore and rehabilitate their skin.

Chemical peeling involves the application of a chemical exfoliant to wound the epidermis and dermis for the removal of superficial lesions and improve the texture of skin. Various acidic and basic chemical agents are used to produce the varying effects of light to medium to deep chemical peels through differences in their ability to destroy skin. The level of penetration, destruction and inflammation determines the level of peeling. The stimulation of epidermal growth through the removal of the stratum corneum without necrosis consists of light superficial peel. Through exfoliation, it thickens the epidermis with qualitative regenerative changes. Destruction of the epidermis defines a full superficial chemical peel inducing the regeneration of the epidermis. Further destruction of the epidermis and induction of inflammation within the papillary dermis constitutes a medium-depth peel. Then, further inflammatory response in the deep reticular dermis induces new collagen production and ground substances which constitutes a deep chemical peel.1 These have now been well classified and usage has been categorized for various degenerative conditions associated with photoaging skin based on levels of penetration. The physician, thus, has tools capable of solving problems that may be mild, moderate or severe with agents that are very superficial, superficial, medium-depth, and deep peeling chemicals. The physician must choose the right agent for each patient and condition.

Indications and Patient Selection
Analyzing the patient with photoaging skin must take into account skin color and skin type as well as degree of photoaging. Various classification systems have been available and I would like to present a combination of three systems that would simplify and help the physician define the right program or therapeutic procedure for his patient. The Fitzpatrick skin type system classifies degrees of pigmentation and ability to tan.2 Graded I through VI, it prognosticates sun sensitivity, susceptibility to photodamage, and ability for facultative melanogenesis (one’s intrinsic ability to tan). In addition, this system classifies skin as to its risk factors for complications during chemical peeling. Fitzpatrick divides skin types I through VI, taking into account both color and reaction to the sun. Skin type I and II are pale white and freckled with a high degree of potential to burn with sun exposure. Three and four can burn but usually is an olive to brown coloration. Five and six are dark brown to black skin that rarely ever burns and usually does not need sunscreen protection (see Table I). The patient with type I or II skin with significant photodamage needs regular sunscreen protection prior to and after the procedure. He, though, has little risk for hypopigmentation or reactive hyperpigmentation after a chemical peeling procedure. The patient, though, with type III through VI skin 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 to prevent these complications.3 Pigmentary risks are generally not a great problem with very superficial and superficial pigment chemical peeling, but may become a significant problem with medium and deep chemical peeling. It can also be a significant risk when regional areas such as lips and eyelids are peeled with a pulsed laser, creating a significant color change in these cosmetic units from the rest of the face. The porcelain white shiny skin seen after taped deep chemical peels in regional areas has been classified as the “alabaster look.” This is an objectionable side effect of deep taped phenol peeling and should be avoided now as patients demand a natural look. The physician must inform the patient of this and other potential problems, especially if the skin type is III through VI. He must justify whether the benefits of the procedure outweigh these risks and, in addition, plan for the appropriate techniques to prevent these unwanted changes in color.

The Glogau system classifies severity of photodamage, taking into account the degree of epidermal and dermal degenerative effects.4 The categorization is I through IV, ranging from mild, moderate, advanced and severe photodamaged skin. These categories are devised to project which patients need therapeutic intervention. Category I or minimal degree photodamage can be treated with light chemical peeling and medial treatment. Category II and III would entail medium-depth chemical peeling while category IV would need deep peeling or resurfacing plus cosmetic surgical intervention for gravitational changes (see Table II). Monheit and Fulton have devised a system of quantitating photodamage developing numerical scores that would fit into corresponding rejuvenation programs.5 In analyzing photodamage, the major categories include dermal with textural changes and epidermal with skin lesions. Dermal 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 quantitated, giving the patient a point score, 1 through 4. In addition, the number and extent of lesions are categorized from freckles, lentigenes, telangiectasias, actinic and seborrheic keratoses, skin cancers, and senile comedones. These also are added in a classification system 1 through 4 and the final score results are tabulated. A total score of 1 through 4 would indicate 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 score of 5 through 9 would include all of the above plus repetitive superficial peeling agents program such as glycolic acid, Jessner’s solution, or lactic acid peels. A score of 10-14 would need a medium-depth chemical peeling, and a score of 15 or above would include deep chemical peeling or laser resurfacing. The patient thus understands during the consultation his degree of photodamage and the necessity for an individual skin rejuvenative program. (see table III)

The peeling agent is a chemical eshcarotic that damage the skin in a therapeutic manner. It is important that the physician understand the patient’s skin and its ability to withstand this damage. The epidermis and stratum corneum have a barrier function against noxious chemicals and some skin types withstand the damage to a greater degree than others while particular skin disorders have a greater tendency to produce side effects and complications from chemical peels, due to poor barrier function or exaggerated inflammatory reactions. Patients with skin disorders such as atopic dermatitis, seborrheic dermatitis, psoriasis, contact dermatitis may find their disease exacerbated in the post-operative period or even develop problems with post-operative healing such as prolonged wound healing, post-erythema syndrome, or contact sensitivity during a post-operative period. Rosacea is a disorder of vasomotor instability in the skin and may develop an exaggerated inflammatory response to the peeling agents. Other important factors include a history of radiation therapy to the proposed facial skin as chronic radiation dermatitis decreases the body’s ability to heal properly. A general rule of thumb is to examine the facial hair in the area treated by radiation and if it is intact, there are enough pilosebaceous units to heal the skin properly after medium or even deep chemical peeling. This, though, is not absolute and one should find in history the dates of radiation treatment and how many rads were used for each individual treatment. Some of our patients with the greatest amount of radiation dermatitis, though, had treatments that were given for acne in the mid fifties and over the years the skin developed the resultant degenerative changes.6 On the other hand, patients with extensive photodamage may require stronger peeling agents and repeated applications of medium-depth peeling solutions to obtain therapeutic results. It is for this reason a careful evaluation of skin types and problems must be assessed.

Herpes simplex can be a post-operative problem with significant morbidity. Patients susceptible should be pre-treated with antiherpetic agents such as acyclovir or valcyclovir to prevent herpetic activation. These patients can be identified in the pre-operative consultation and placed on appropriate therapy at the time of the chemical peel. All anti-herpetic agents act by inhibiting viral replication in the intact epidermal cell. The significance of this in peeling is that the skin must be reepithelialized before the agent has its full effect. Thus, the antiviral agent must be continued in deep chemical peeling for the entire two weeks, or in medium-depth peeling for at least ten days.7

The chief indications for medium and deep chemical peeling are associated with the reversal of actinic changes such as photodamage, rhytides, actinic growths, pigmentary dyschromias, and acne scars.8 The physician thus can use his classification systems to quantitate and qualitate the level of photodamage and prescribe the appropriate chemical peeling combination.

Medium-depth chemical peeling
Medium-depth chemical peeling is defined as controlled damage from a chemical agent to the epidermis and papillary dermis resulting in specific regenerative changes that can be performed in a single setting. Agents currently used include combination products – Jessner’s solution, 70% glycolic acid, and solid carbon dioxide with 35% trichloroacetic acid. The benchmark for this level peel was 50% trichloroacetic acid. It has traditionally achieved acceptable results in ameliorating fine wrinkles, actinic changes, and pre neoplasia. However, since TCA itself is an agent more likely to be fraught with complications, especially scarring, in strengths of 50% or higher, it has fallen out of favor as a single agent chemical peel.9 It is for this reason that the combination products along with a 35% TCA formula have been found equally effective in producing this level of control damage without the risk of side effects.

Brody first developed the use of solid CO2 applied with acetone to the skin as a freezing technique prior to the application of 35% trichloroacetic acid. The preliminary freezing appears to break the epidermal barrier for a more even and complete penetration of the 35% trichloroacetic acid.10

Monheit then demonstrated the use of Jessner’s solution prior to the application of 35% trichloroacetic acid. The Jessner’s solution was found effective in destroying the epidermal barrier by breaking up individual epidermal cells. This also allows a deeper penetration of the 35% TCA and a more even application of the peeling solution.11 Similarly, Coleman has demonstrated the use of 70% glycolic acid prior to the application of 35 % trichloroacetic acid. Its effect has been very similar to that of Jessner’s solution.12 (Table IV)

All three combinations have proven to be as effective as the use of 50% trichloroacetic acid with a greater safety margin. The application of acid and resultant frosting are better controlled with the combination so that the “hot spots” with higher concentrations of TCA can be controlled, creating an even peel with less incidence of dyschromias and scarring. The combination peel produces an even, uniform peel. The Monheit version of the Jessner’s solution – 35% TCA peel is a relatively simple and safe combination. The technique is used for mild-to-moderate photoaging including pigmentary changes, lentigines, epidermal growths, dyschromias, and rhytids. It is a single procedure with a healing time of seven to ten days. It is useful also to remove diffuse actinic keratoses as an alternative to chemical exfoliation with topical 5-fluorouracil chemotherapy. Topical chemotherapy is applied for three weeks creating erythema, scabs and crusts for up to six weeks.13 The combination peel will produce similar therapeutic benefits within ten days of healing. It thus reduces the morbidity significantly and gives the cosmetic benefits of improved photoaging skin.

The procedure is usually performed with mild preoperative sedation and nonsteroidal antiiflammatory agents. The patient is told that the peeling agent will sting and burn temporarily and aspirin is given before the peel and continued through the first twenty-four hours if the patient can tolerate the medication. Its inflammatory effect is especially helpful in reducing swelling and relieving pain. If given before surgery, it may be all the patient requires during the postoperative phase. For full-face peels, though, it is useful to give preoperative sedation (diazepam 5 to 10 mg orally) and mild analgesia, meperidine 25 to 50 mg (Demerol – Winthrop, New York), and hydroxyzine hydrochloride 25 mg intramuscularly (Vistaril – Lorec, New York). The discomfort from this peel is not long lasting, so short acting sedatives and analgesics are all that are necessary.14

Vigorous cleaning and degreasing is necessary for even penetration of the solution. The face is scrubbed gently with Ingasam (Septisol - Vestal Laboratories, St. Louis, Missouri) four-inch by four-inch gauze pads and water, then rinsed and dried. Next, an acetone preparation is applied to remove residual oils and debris. The skin is essentially debrided of stratum corneum and excessive scale. A thorough degreasing is necessary for an even penetrant peel. The physician should feel the dry, clean skin to check the thoroughness of degreasing. If oil is felt, degreasing should be repeated. A splotchy peel is usually the result of uneven penetration of peel solution due to residual oil or stratum corneum, and a result of inadequate degreasing.

After thorough cleaning, the Jessner’s solution is applied with either cotton-tip applicators or 2” x 2” gauze. (Table V) The Jessner’s solution is applied evenly with usually one or two coats to achieve a light but even frosting. The frosting achieved with Jessner’s solution is much lighter than that produced by TCA and the patient is usually uncomfortable, feeling only heat. A mild erythema appears with a faint tinge of splotchy frosting over the face. Even strokes are used to apply the solution to the unit area covering the forehead to the cheeks to the nose and chin. The eyelids are treated last creating the same erythema with blotchy frosting. (Fig 1)

The TCA is painted evenly with one to four cotton-tipped applicators that can be applied over different areas with light or heavier doses of the acid. Four cotton-tipped applicators are applied in broad strokes over the forehead and also on the medial cheeks. Two mildly soaked cotton-tipped applicators can be used across the lips and chin, and one damp cotton-tipped applicator on the eyelids. Thus, the dosage of application is technique dependent on the amount used and the number of cotton-tipped applicators applied. The cotton-tipped applicator is useful in quantatiting the amount of peel solution to be applied.

The white frost from the TCA application appears complete on the treated area within 30 seconds to 2 minutes. Even application should eliminate the need to go over areas a second or a third time, but if frosting is incomplete or uneven, the solution should be reapplied. TCA takes longer to frost than Baker’s formula or straight phenol, but a shorter period of time than the superficial peeling agents do. The surgeon should wait at least 3 to 4 minutes after the application of TCA to ensure the frosting has reached its peak. He then can document the completeness of a frosted cosmetic unit and touch up the area as needed. Areas of poor frosting should be retreated carefully with a thin application of TCA. The physician should achieve a level II to level III frosting. Level I frosting is erythema with a stringy or blotchy frosting, seen with light chemical peels. Level II frosting is defined as white-coated frosting with erythema showing through. A level III frosting, which is associated with penetration through the papillary dermis, is a solid white enamel frosting with little or no background of erythema.15 A deeper level III frosting should be restricted only to areas of heavy actinic damage and thicker skin. Most medium-depth chemical peels use a level II frosting and this is especially true over eyelids and areas of sensitive skin. Those areas with a greater tendency to scar formation, such as the zygomatic arch, the bony prominences of the jawline, and chin, should only receive up to a level II frosting. Overcoating trichloroacetic acid will increase its penetration so that a second or third application will drive the acid further into the dermis, creating a deeper peel. One must be careful in overcoating only areas in which the take up was not adequate or the skin is much thicker. (Fig II)

Anatomic areas of the face are peeled sequentially from forehead to temple to cheeks and finally to the lips and eyelids. The white frosting indicates keratocoagulation or protein denaturation of keratin and at that point the reaction is complete. Careful feathering of the solution into the hairline and around the rim of the jaw and brow conceals the line demarcation between peeled and nonpeeled areas. The perioral area has rhytids that require a complete and even application of solution over the lip skin to the vermilion. This is accomplished best with the help of an assistant who stretches and fixates the upper and lower lips which the peel solution is applied.

Certain areas and skin lesions require special attention. Thicker keratoses do not frost evenly and thus do not pick up peel solution. Additional applications rubbed vigorously into the lesion may be needed for peel solution penetration. Wrinkled skin should be stretched to allow an even coating of solution into the folds and troughs. Oral rhytides require peel solution to be applied with the wood portion of a cotton-tipped applicator and extended into the vermilion of the lip. Deeper furrows such as expression lines will not be eradicated by peel solution and thus should be treated like the remaining skin.

Eyelid skin must be treated delicately and carefully. A semidry applicator should be used to carry the solution within 2 to 3 mm of the lid margin. The patient should be positioned with the head elevated at 30 degrees and the eyelids closed. Excess peel solution on the cotton tip should be drained gently on the bottom before application. The applicator is then rolled gently on the lids and periorbital skin. Never leave excess peel solution on the lids because the solution can roll into the eyes. Dry the tears with a cotton-tipped applicator during peeling because they may pull peel solution to the puncta and eye by capillary attraction. (Fig III) The solution should be diluted immediately with cool saline compresses at the conclusion of the peel. The Jessner’s-TCA peel procedure is as follows:
1. The skin should be cleaned thoroughly with Septisol to remove oils.
2. Acetone or acetone alcohol is used to further debride oil and scale from the surface of the skin.
3. Jessner’s solution is applied.
4. Thirty-five percent TCA is applied until a light frost appears.
5. Cool saline compresses are applied to dilute the solution.
6. The peel will heal with 0.25% acetic acid soaks and a mild emollient cream.
There is an immediate burning sensation as the peel solution is applied, but this subsides as frosting is completed. Cool saline compresses offer symptomatic relief for a peeled area as the solution is applied to other areas. The peel reaction is not neutralized by saline solution as the reaction is completed when frosting occurs.16 The compresses are placed over the face for 5 to 6 minutes after the peel until the patient is comfortable. The burning subsides fully by the time the patient is ready to be discharged. At that time, most of the frosting has faded and a brawny desquamation is beginning.

Postoperatively, edema, erythema, and desquamation are expected. With periorbital peels and even forehead peels, eyelid edema can occur and may be enough to close the lids. For the first 24 hours, the patient is instructed to soak four times a day with a 0.25% acetic acid compress made of 1 tablespoon white vinegar in 1 pint of warm water. A bland emollient is applied to the desquamating areas after soaks. After 24 hours, the patient can shower and clean gently with a mild nondetergent cleanser. The erythema intensifies as desquamation becomes complete within 4 to 5 days. Thus, healing is completed within 1 week to 10 days. At the end of 1 week, the bright red color has faded to pink and has the appearance of a sunburn. This can be covered by cosmetics and will fade fully within 2 to 3 weeks.

The medium-depth peel is dependent on three components for therapeutic effect: (1) degreasing, (2) Jessner’s solution, and (3) 35% TCA. The amount of each agent applied creates the intensity and thus the effectiveness of this peel. The variables can be adjusted according to the patient’s skin type and the areas of the face being treated. It is thus the workhorse of peeling and resurfacing in my practice as it can be individuated for most patients we see.

The medium-depth chemical peel thus has five major indications: (1) destruction of epidermal lesions – actinic keratoses, (2) resurfacing the level II or III moderate photoaging skin, (3) pigmentary dyschromias, (4) mild acne scars, (5) blending photoaging skin with laser resurfacing and deep chemical peeling.

1. Actinic keratoses – This procedure is well suited for the patient with epidermal lesions such as actinic keratoses which has required repeated removal with either cryosurgery or chemoexfoliation (5-fluoruracil). The entire face can be treated as a unit or subfacial cosmetic unit such as forehead, temples, and cheeks, and can be treated independently. Active lesions can be removed, as well as incipient growths as yet undetected, will be removed as the epidermis is sloughed. Advantages for the patient with photodamaged skin include a limited recovery period – 7 to 10 days, with little post operative erythema after healing. There is little risk of pigmentary changes either hypopigmentation or hyperpigmentation, thus, the patient can return to work after the skin has healed.(Fig IV)
2. Moderate photoaging skin – Glogau level II or III damage responds well to this peeling combination with removal of the epidermal lesions and dermal changes that will freshen photoaging characterized as sallow, atrophic skin with fine rhytides. This peel is favored over deeper resurfacing procedures such as laser and deep peel in that it will heal in ten days with minimal risk of textural or color complications. It, though, is only designed for medium-depth damage. (Fig V)
3. Pigmentary dyschromias - Though color change can be treated with repetitive chemical peeling, the medium-depth peel will be a single treatment preceded and followed by the use of bleaching agents and retinoic acid.17 In most cases, the pigmentary problems are resolved with this single peel as an adjunct to the skin care program. (Fig VI)
4. Blending other resurfacing procedures – In a patient in which there is advanced photoaging changes such as crow’s feet and rhytides in the periorbital and/or perioral area with medium-depth changes on the remaining face, a medium-depth peel can be used to integrate these procedures together. That is, laser resurfacing or deep chemical peeling can be performed over the periorbital and perioral areas that has more advanced photoaging changes, while the medium-depth chemical peel is used for the rest of the face. This will blend the facial skin as a unit so that the therapeutic textural and color changes will not be restricted to one area. The patients requiring laser resurfacing in a localized cosmetic unit will have the remaining areas of their face blended with this medium-depth chemical peel. Patients having laser resurfacing or deep peeling to the perioral or periorbital areas alone develop a pseudo hypopigmentation that is a noticeable deformity. The patient requiring laser resurfacing at a localized cosmetic unit will have the remaining areas of their face blended with this medium-depth peel. The alternative – a full-face deep peel or laser resurfacing has an increased morbidity, longer healing and risk of scarring over areas such as the lateral jaw line, malar eminences, and forehead. If deep resurfacing is needed only over localized areas such as perioral or periorbital face, a blending medium-depth peel does reduce morbidity and healing time.18 (Fig VII)

Deep chemical peeling
Glogau Level III and IV photodamage requires deep chemical peeling. This entails the use of either trichloroacetic acid above 50%, or the Gordon-Baker phenol peel. Laser resurfacing can also be used to reliably reach this level of damage. TCA above 45% has been found to be unreliable and dangerous with a high incidence of scarring and postoperative complications. For this reason, it is not included as a preferred treatment method for deep chemical peeling. The Baker-Gordon phenol peel has been used successfully for over 40 years for deep chemical peeling and produces reliable results.(Table VI) It is a labor-intensive procedure that must be taken seriously as all major surgical procedures are.

The patient requires preoperative sedation with an intravenous line and preoperative IV hydration. Usually a liter of fluid is given preoperatively and in addition, a liter of fluid is given during the procedure. This is helpful in decreasing the phenol concentration from the serum. For this reason, one must be concerned with phenol absorption through the skin and the resultant serum concentration of phenol through cutaneous absorption. Methods to limit this include:
1. IV hydration prior to the procedure and during the peel to flush the phenolic products through the serum.
2. Extending the time of application for a full-face peel over one and one-half hours. Baker’s solution is applied to each cosmetic unit with a fifteen-minute wait in between each unit. That is, the forehead, cheeks, chin, lips, and eyelids are each given a fifteen-minute period of time for a total of an hour to an hour and a half for the procedure.
3. All patients are monitored and if there is any electrocardiographic abnormality, i.e. PVC, or PAC, the procedure is stopped and the patient is watched carefully for other signs of toxicity.
4. Many physicians believe that O2 given during the procedure can be helpful in preventing arrhythmic complications.
5. Any patient with a history of cardioarrhythmia, hepatic or renal compromise, or on medications that give a propensity for arrhythmias, should not undergo the Baker-Gordon phenol peel.19

The patient undergoing deep chemical peeling must recognize the significant risk factors, the increased morbidity, and possible complications involved in this procedure so that the benefits can be weighed positively against these particular factors. In the hands of those that do this technique regularly, it is a reliable and safe method of rejuvenating advanced to severe photoaged skin including deeper perioral rhytids, periorbital rhytids and crow’s feet, forehead lines and wrinkles, as well as the other textural and lesional changes associated with the more severe photoaging process.

There are two methods for deep chemical peeling; Baker’s formula phenol unoccluded, and Baker’s formula phenol occluded with tape. Occlusion is accomplished with the application of waterproof zinc oxide tape such as one half inch Curity tape. The tape is placed directly after the phenol is applied to each individual cosmetic unit. Tape occlusion increases the penetration of the Baker’s phenol solution and is particularly helpful for deeply lined “weather-beaten” faces. A taped Baker’s formula phenol peel creates the deepest damage in mid-reticular dermis and this form of chemical peeling should only be performed by the most knowledgeable and experienced cosmetic surgeons who understand the risks of over penetration and deep damage to the reticular dermis.20 The unoccluded technique as modified by McCollough involves more skin cleansing and application of more peel solution. On the whole, this technique does not produce as deep a peel as the occluded method.21

When the Baker’s peel was first popularized in the seventies, taping and dry healing would produce both color and textural changes on most patients. This included hypopigmentation with alabaster skin texture. Most patients were told that they would need make-up to disguise the color and textural changes. Today, this is unacceptable in this day when natural appearance of skin texture is so important.
The Baker-Gordon formula for this peel was first described in 1961, and since then has been used successfully for over 25 years. The Baker-Gordon formula of phenol (See table IV) penetrates further into the dermis than full-strength undiluted phenol because full-strength phenol allegedly causes an immediate coagulation of epidermal keratin proteins and self blocks further penetration. Dilution to approximately 50 to 55 % in the Baker-Gordon formula causes keratolysis and keratocoagulation resulting in greater penetration. The liquid soap, Septisol, is a surfactant that reduces skin tension allowing a more even penetration. Croton oil is a vesicant and epidermolytic agent that enhances phenol absorption. The freshly prepared formula is not miscible, but rather is a suspension and must be stirred in a clear glass medicine cup immediately before application to the patient. Though the mixture can be stored in an amber glass bottle for short periods, this is usually unnecessary and should be reformulated on a regular basis.

Techniques
Before the administration of anesthesia, the patient’s face is marked in seated position noting landmarks such as the mandibular angle, the chin, the preauricular sulcus, the orbital rim, and the forehead. The markings delineate the borders of the peel throughout the limits of the face and slightly over the mandibular rim to blend any color change. This peel does require sedation. An intravenous combination such as fentanyl citrate (Sublimaze) and midazolam (Versed) can be administered intravenously by an anesthetist while the patient is monitored and given intravenous sedation. It is helpful to use local nerve blocks along the supraorbital, infraorbital nerve, and mental nerve with Marcaine, which should provide some local anesthesia for up to four hours. This is helpful with post-operative pain.

The patients should arrive n.p.o., and have shaved and cleansed their face the morning of surgery. The face then is cleansed and degreased with a keratolytic agent such as hexochlorophine with alcohol (Septisol) over the entire face with emphasis placed on oily areas such as the nose, the hairline, and mid facial cheeks. A thorough and evenly distributed cleansing or degreasing of the face will assure a more uniform peel without skipped areas.

The phenol chemical agent is then applied sequentially to the six aesthetic units: forehead, perioral, right and left cheeks, nose, and periorbital areas. Each cosmetic area takes 15 minutes for application, allowing 60 to 90 minutes for the entire procedure. Cotton-tipped applicators are used with a similar technique as discussed on the medium-depth Jessner – 35% TCA peel. Less agent, though, is used because frosting occurs very rapidly. The last area for the peel is the periorbital skin on which the chemical is applied with only damp cotton-tipped applicators taken care to keep the drops away from the eye and keep tears off the skin. Tearing may allow the peel solution to reach the eye by capillary attraction. It is important to remember that water dilution of this chemical may increase the absorption; therefore, if the chemical does get into the eye, these should be flushed with mineral oil rather than water. An immediate burning sensation is present for 15 to 20 seconds, and then subsides. The pain returns in 20 minutes and persists for 6 to 8 hours.

Following the full application of peel solution, the white frosting gradually develops a brawny brown color and the tape can be applied for an occluded peel. Ice packs can be applied at the conclusion of the peel for comfort, and if this is an untaped peel, petrolatum is used. A biosynthetic dressing such as Vigilon or Flexzan can be used for the first 24 hours. The patient is usually seen in 24 hours to either remove the tape or the biosynthetic dressing and to monitor the healing. It is at this time the patient is again reinstructed in the method of compresses and occlusive ointments or dressings. It is important to keep the skin crust-free.

The four stages of wound healing are apparent after a deep chemical peel. They include: (1) inflammation, (2) coagulation, (3) reepithelializaiton, and (4) fibroplasia.23 At the conclusion of the chemical peel, the inflammatory phase has already begun with a brawny, dusky erythema that will progress over the first 12 hours. This is an accentuation of the pigmented lesions on the skin as the coagulation phase separates the epidermis producing serum exudation, crusting, and pyoderma. It is during this phase that it is important to use debridant soaks and compresses as well as occlusive salves. These will remove the sloughed, necrotic epidermis and prevent the serum exudate from hardening as crust and scab. I prefer the use of ¼ % acetic acid soaks found in the vinegar/water preparation (1 teaspoon white vinegar, 1 pint warm water), as it is antibacterial, especially against pseudomonas and gram negatives. In addition, the mildly acidic nature of the solution is physiologic for the healing granulation tissue, and mildly debridant, as it will dissolve and cleanse the necrotic material and serum. I prefer to use bland emollients and salves such as Vaseline petrolatum, Eucerin, or Aquaphor, as the skin can be monitored carefully day by day for potential complications.

Reepithelializtaion begins on day 3 and continues until day 10 to 14. Occlusive salves promote faster reepithelialization and less tendency for delayed healing, which may occur with dry crusting. The final stage of wound healing – fibroplasia, will continue well beyond the initial closure of the peeled wound and continues with neoangiogenesis and new collagen formation for 3 or 4 months. Prolonged erythema may last 2 to 4 months in unusual cases of sensitive skin or with contact dermatitis. New collagen formation can continue to improve texture and rhytides for a period up to 4 months during this last phase of fibroplasia.

Complications
Many of the complications seen in peeling can be recognized early on during healing stages. The cosmetic surgeon should be well acquainted with the normal appearance of a healing wound and its time frame for both medium and deep peeling. Prolongation of the granulation tissue phase beyond a week to ten days may indicate delayed wound healing. This could be the result of viral, bacterial, or fungal infections, contact dermatitis interfering with wound healing, or other systemic factors. A red flag should alert the physician to carefully investigate and institute prompt treatment to forstall potential irrepairable damage that may result in scarring.24

Complications can be caused either intraoperatively or postoperatively. The two inherent erros that lead to intraoperative complications are (1) incorrect peel pharmacology and (2) accidental solution misplacement. It is the physician’s responsibility to know the solution and its concentration is correct. Trichloroacetic acid concentrations should be measured weight by volume as this is the standard for measuring depth of peel. Glycolic acid and lactic acid solutions as well as Jessner’s solution must be checked for expiration date as the potency decreases with time. Alcohol or water absorption may inappropriately increase the potency, so one must assure the shelf life is appropriate. The peel solution should be applied with cotton-tipped applicators and in medium and deep peels, it is best to pour the peel solution in a secondary container rather than apply the solution spun around the neck of the bottle. Intact crystals may give the solution a higher concentration of solution as it is taken directly from its container. One should be careful to apply the solution to its appropriate location and not to pass the wet cotton-tipped applicator directly over the central face where a drop may inadvertenly get on sensitive areas such as the eyes. Saline and bicarbonate of soda should be available to dilute TCA or neutralize glycolic acid if inappropriately placed in the wrong area. Likewise, mineral oil should be present for Baker’s phenol peels. Postoperative complications can result from local infection or contact dermatitis. The best deterrent for local infection is the continuous use of soaks to debride crusting and necrotic material. Strep and staph infection can occur under biosynthetic membranes or thick occlusive ointments. The use of ¼ % acetic acid soaks seems to deter this as well as the judicious removal of the ointment with each soak. Staph, e. coli, or even pseudomonas may result from improper care during healing and should be treated promptly with the appropriate oral antibiotic.

Frequent postoperative visits are necessary to recognize the early onset of a bacterial infection. It may present itself as delayed wound healing, ulcerations, build up of necrotic material with excessive scabbing, crusting, purulent drainage, and odor. Early recognition and institution of appropriate antibiotics will prevent the spread of infection, heal the skin, and prevent scarring.

Herpes simplex infection is the result of reactivation of the herpes simplex virus on the face and most commonly on the perioral area. A history of previous HSV infection should necessitate the use of prophylactic oral antiviral medications. Patients with a positive history can be treated with 400 mg of acyclovir three times a day beginning on the day of the peel and continuing for 7 to 14 days, depending on whether it is a medium-depth or deep chemical peel. I prefer to treat all patients with antiviral agents irregardless of a positive history as many patients do not remember prior herpes simplex infection that may have occurred years ago. The mechanism of action of all antiviral agents is to inhibit viral replication in the intact epidermal cell. This would mean that the drug would not have an inhibitory effect until the skin is reepithelialized, which is 7 to 10 days in medium and deep peels. In the past, these agents were discontinued at 5 days and in treated patients, clinical infection became apparent in 7 to 10 days.24

Active herpetic infections can easily be treated with antiviral agents and caught early, they usually do not scar.

Delayed wound healing and persistent erythema are signs that the peel is not healing normally. The cosmetic surgeon must know the normal time table for each of the healing events so that he may recognize what time healing is delayed or the erythema has not fading adequately. Delayed wound healing may respond to physician debridement if an infection is present, corticosteroids if due to contact allergic or contact irritant dermatitis along with the change of the offending contact agent, or protection with a biosynthetic membrane such as Flexzan or Vigilon. When this diagnosis is made, these patients must be followed daily with dressing changes and a close watch on the healing skin.

Persistent erythema is a syndrome where the skin remains erythematous beyond what is normal for the individual peel. A superficial peel loses its erythema in 3 to 5 days, a medium-depth peel within 15 to 30 days, and a deep chemical peel within 60 to 90 days. Erythema and/or pruritus beyond this period of time is considered abnormal and fits this syndrome. It may be contact dermatitis, contact sensitization, reexacerbation of prior skin disease, or a genetic susceptibility to erythema. It though is a red flag that also indicates a sign of potential scarring. Erythema is the result of the angiogenic factors stimulating vasodilation which indicates the phase of fibroplasia is being stimulated for a prolonged period of time. For this reason, it can be accompanied by skin thickening and scarring. It should be treated promptly and appropriately with topical steroids, systemic steroids, intralesional steroids if thickening is occuring, and skin protection which would eliminate the factors of irritancy and allergy. If thickening or scarring becomes evident, other measures that be helpful include the daily use of silicone sheeting and the dye pulsed vascular laser to treat the vascular factors. With prompt intervention, scarring in many cases can be averted.

Conclusion
The physician has the responsibility of choosing the correct modality to treat skin conditions such as photoaging skin, scars, dyschromias, and the removal of skin growths. There are many agents available including the three levels of chemical peels reviewed. It is the responsibility of the physician to have thorough knowledge of all of these tools to give each patient the correct treatment his condition warrants.