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Introduction and Indications for Medium to Deep Chemical Peels

Prior to the development of laser resurfacing, chemical peels were among the sole methods by which to resurface the skin. For decades, medium and deep peels have been used to treat a number of skin conditions in ethnically diverse patients . Despite the growing popularity of lasers, peels continue to rank among the most popular cosmetic procedures performed today [1] showing a 4% increase to 1.36 million procedures in the USA during 2016. The two most commonly used acids for medium and deep peels are trichloroacetic acid (TCA ) and phenol . The most common indications for chemical peels are actinic keratosis , photodamage , ephelides/lentigines, rhytides, post-inflammatory hyperpigmentation, certain types of acne scars, and melasma. By varying the concentration of the solution or the peeling agent , peels can be used to treat the skin of the neck, chest, and upper extremities.

Chemical peeling agents can be classified as protein denaturants (TCA, phenol) or as keratolytic agents (glycolic acid, lactic acid, salicylic acid, and low strength phenol). It is the protein denaturing property that is desired in medium and deep peeling to achieve wounding through the epidermis and into different levels of the dermis. Medium depth peels penetrate through the epidermis and into the papillary dermis level while deep peels penetrate through all the layers of the skin and reach the upper reticular dermis. Extremely deep peels into the mid reticular dermis can be performed but the risk of hypertrophic scarring, hypopigmentation , and permanent textural change make that type of peel very risky.

What Accounts for Chemical Peel Penetration?

A lot of importance is given to acid concentration when it comes to phenol and TCA peels . However, peel depth penetration is determined by more than just acid concentration. TCA is hydrophilic; therefore oily skin would serve as a barrier to peel penetration. Phenol is lipophilic and will penetrate through the skin very quickly. Furthermore, we now understand the important role croton oil plays in driving phenol peels deeper.

The Following Factors Influence Peel Penetration

Concentration

Higher concentration of TCA or phenol will penetrate through the skin to a deeper level than the same volume of a lower concentration TCA or phenol. The higher the acid concentration, the more protein coagulation that occurs. Thus, the acid will reach a deeper depth with each application.

Volume

As TCA and phenol acids penetrate the skin, their effect stops once enough protein coagulation has occurred to negate the acid that was applied. Thus, further peel penetration would require more acid be applied to the skin to drive the peel deeper. Therefore, thicker skin would require more acid volume than thinner skin to achieve a peel to the same depth.

Body Surface Area

Body surface area (BSA ) is another factor. A fixed volume and concentration of peel solution will penetrate more deeply if the entire volume is applied over a small area of skin as opposed to the same volume being applied to a larger surface area.

Skin Thickness

Epidermal and dermal thickness varies by patient age, gender, anatomic location, and ethnicity. Chemical peel solutions will reach the dermis more quickly in thinner skin patients than those with thicker skin. Therefore, the physician will need to adjust either the volume or concentration of the peeling solution.

Skin Oiliness

Sebum and thicker, oilier skin is more challenging for TCA penetration. Properly degreasing the skin will allow TCA to penetrate more deeply than it would otherwise. Patients with oily skin will require either more volume of TCA or a higher concentration of TCA to penetrate through the sebum. Alternatively, patients who are very oily may require systemic therapy with isotretinoin for a month or two to reduce sebum production prior to the peel. However, if a patient is treated with isotretinoin, a waiting period of 3 months before peeling of the skin may be suggested to ensure proper wound healing.

Croton Oil Concentration

The most recognized formula for deep phenol peeling is the Baker & Gordon formula in which patients were peeled to the mid reticular dermis. While the results were dramatic, the risk of scarring and permanent hypopigmentation greatly reduced the number of patients that could or would undergo this procedure. Two researchers, Stone (2b) [2] and Hetter (2b) [3], studied the peel depth penetration achievable by varying either the phenol acid or croton oil concentration .

Other Factors Influencing Peel Depth

Pre-peel thinning of the stratum corneum with topical retinoids or fruit acids will help the peel solution penetration more easily. Furthermore, the amount of rubbing or pressure applied to the skin when performing the peel will also drive the solution deeper.

Effectiveness of Chemical Peels for Treating Melasma

Melasma is one of the most common complaints of patients presenting to the dermatologist. It remains a challenging condition to treat. Many modalities, while giving initial improvement, are associated with a significant relapse rate.

Kumari and Thappa (2b) [4] looked at glycolic acid (GA) versus TCA peels in patients with melasma. Forty patients with epidermal (78%) or mixed melasma (22%) (epidermal and dermal) were randomized into two groups. “Most” patients were phototype IV–VI. All patients had baseline melasma area and severity index (MASI ) scores calculated. The GA group received pretreatment with 12% GA cream and a sunscreen SPF 15 to use daily for 2 weeks prior to the peel. The TCA group was given 0.1% tretinoin nightly and sunscreen SPF 15 daily starting 2 weeks before the peels. Patients were then peeled every 2 weeks with escalating concentration or contact time to the peel solutions. Peel 1: 20% GA or 10% TCA left on for 2 min. Peel 2: 20% GA or 10% TCA for 4 min. Peel 3: 35% GA and 20% TCA for 2 min. Peel 4: 35% GA or 20% TCA for 4 min. More peels were performed after these initial four if patients showed slow or inadequate response. At the conclusion of all the peels, patients were treated with 2% hydroquinone cream nightly and an SPF 15 daily to maintain the results. The study showed that the GA group had MASI score reductions from 26.6 to 5.6 (79%) and the TCA group showed a reduction from 29.1 to 8.2 (73%). The difference between the GA and TCA group was not statistically significant. Similarly, the subjective improvement scores showed a good to very good response in 75% of GA patients and 65% of TCA patients. The difference between the two was not statistically significant. During the recovery periods, the GA patients were able to continue working whereas the TCA patients often had to take time off of work. At 6 months, two of the GA patients showed relapse. There is no mention as to which type of melasma (epidermal or mixed) did better for the TCA group. However, the GA acid group was evaluated for response with statistically significant reduction in MASI for the epidermal melasma patients (79% reduction) but not for the mixed-type melasma (27.8%).

Puri (2b) [5] compared 15% TCA peels (n = 15) versus 35% GA peels (n = 15) in 30 epidermal melasma patients. Patients were primed for 2 weeks prior to the peels with 2% Kojic acid or 0.25% tretinoin. There is no mention of SPF use. MASI scores were calculated at baseline and after each peel. Peels were performed at 3-week intervals for six sessions or once the melasma was clear (whichever occurred first). Subjectively, patients noted a good or very good response in 70% of the GA group and 64% of the TCA group . The difference between the two groups was not statistically significant. MASI scores showed a statistically significant improvement from baseline in both groups with the TCA group changing from 22.3 to 5.6 and the GA group changing from 23.6 to 4.25. The difference between the two groups’ MASI scores was not statistically significant. Subjects found the GA peel easier to tolerate and that it required no time off from activities. The authors conclude that both peels were equally effective in the treatment of melasma. This study fails to mention the average number of peels needed per group, and there is no mention of the contact time that the GA peel was left on the skin. Furthermore, patient phototypes were not mentioned.

Safoury et al. (2c) [6] compared 15% TCA peels to a modified Jessner’s Peel + 15% TCA peel in patients with phototypes III or IV. A modified Jessner’s solution has salicylic acid, lactic acid, and citric acid (in place of resorcinol). Twenty patients with epidermal melasma were treated in a split-face, single-blinded manner. Prior to the peels, patients were primed for 2 weeks with a 10% zinc oxide sunblock daily and adapalene 0.1% gel nightly. The treating physician was not blinded. The left malar area was treated with the modified Jessner’s solution until erythema appeared. Then a 15% TCA solution was in a uniform coat to the whole face including the left malar “until frosting.” Peels were repeated every 10 days until the melasma cleared or until a maximum of eight peels. MASI scores decreased from 4.46 to 2.04 on the TCA side (54.26%) and from 4.35 to 1.23 on the combination Jessner/TCA side (71.72%). Follow-up at 8 weeks showed a slight worsening of MASI scores to 2.27 (TCA) and 1.67 (Jessner/TCA), but these scores remained statistically significantly lower than the baseline. No comparison of scores were made between the two sides. No mention was made of the average number of peels performed. The authors conclude that the combination peel is superior to TCA alone.

Abdel-Meguid et al. (2b) [7] performed a single-blinded, split-face trial of 20–25% TCA peels versus Jessner + 20–25% TCA peels in 24 patients with phototypes IV–V. Patients were primed with 2% hydroquinone cream nightly and sunscreen daily for 2 weeks prior to the peels. Peels were performed six times at 2-week intervals. Patients were randomized to left or right cheek treatments with Jessner+TCA and TCA alone. The first three peels were with 20% TCA, and the last three peels were with 25% TCA. MASI scores were calculated at baseline and at the conclusion of the peels. Fourteen patients had epidermal melasma, and ten had mixed-type (epidermal and dermal) melasma. Four patients were dropped for non-compliance. Results showed a statistically significant decrease in MASI scores with either modality: Jessner + TCA (67.75% improvement) and TCA alone (48.60% improvement). Furthermore, the difference in improvements between the two modalities was statistically significant (p < .05). There is no mention of long-term follow up to evaluate relapse. Furthermore, there is no breakdown of response by melasma type. The authors conclude that both modalities are effective in improving melasma but that the Jessner + TCA combination is more efficacious.

Soliman et al. (2b) [8] evaluated 20% TCA peels versus 20% TCA peels + topical ascorbic acid cream in 30 patients with epidermal melasma with skin phototypes III or IV . Patients were randomized into two groups: group A 15% TCA peels and group B 15% TCA peels with home use of a topical ascorbic acid cream. All patients were primed with 2 weeks of 0.05% tretinoin gel daily and 4% hydroquinone daily and SPF > 15. In addition to these agents, group B received a 5% ascorbic acid cream to apply daily as well. MASI scores were calculated at the baseline, after peels were concluded, and at a 16-week follow-up. Peels were performed with 20% TCA weekly until melasma cleared or for a maximum of 6 sessions. Results for group A showed a MASI score reduction of 34.4% (15.31–10.107). This increased to an overall reduction of 20.06% by week 16. Results for group B showed a MASI score reduction of 61.75% (13.753–5.260). This increased by week 16 to reflect an overall reduction of 43.79% in group B. Comparing both groups showed a statistically significant reduction in MASI in group B over group A (p < .001). Patients rated themselves as good, marked, or moderate improvement in 13 of 15 patients (86.66%) in group B and 10 of 15 patients (66.66%) in group A. By week 16, group A showed that results maintained in 48%, worsened in 33%, and continued to improve in 19% of the cases. By week 16, group B showed results maintained in 60%, worsened in 13%, and continued to improve in 27% of the cases. All but two patients in group B required all six peel sessions.

Moubasher et al. (2b) [9] evaluated different concentrations of TCA peels versus 2 different Q-switched neodymium-doped yttrium-aluminum-garnet laser (Qs-Nd:YAG) laser treatments on 65 female patients, phototypes III to V. Patients were assigned to four groups. There was no special priming of the skin before or after treatments, only the use of topical sunscreen with an SPF > 50. MASI scores were calculated at baseline and after the treatments were completed. Group 1: 15 patients with epidermal melasma treated with 20% TCA. Group 2: 20 patients with epidermal, dermal, or mixed melasma were treated with 30% TCA. Group 3: 15 patients with dermal and mixed melasma were treated with 30% TCA. All peels were repeated at 2 week intervals up to eight sessions or until melasma clearance was achieved. Group 4: 15 patients were treated with Qs-Nd:YAG for epidermal melasma (7 patients treated with 532-nm) and dermal or mixed melasma (8 patients treated with 1064-nm). All laser treatments were monthly for up to six sessions or until clearance was achieved. Patients were monitored for 3 months after treatment to evaluate for recurrence. Results showed the greatest reduction in MASI scores (64.7% improvement) in group 2 compared to group 1 (39.9%), group 3 (24.7%), and group 4. Group 4 showed worsening of MASI scores in the 532-nm group (−83.6%) and the 1064-nm group (−19.1%). Epidermal melasma (52% MASI reduction) improved more than the dermal type (12.1% MASI reduction) (p = .0029), whereas epidermal versus mixed-type melasma (49.5% MASI reduction) showed similar amounts of improvement (p = .77). Patients were “very satisfied” in group 2 (50%) followed by group 1 (40%), and then group 3 (6.7%). All patients (100%) in group 4 were “unsatisfied” followed by group 3 (46.7%), group 1 (6.7%), and group 2 (5%). By 3 months, there was a 32% recurrence rate. The authors conclude that 25% TCA peels were the most effective for melasma and that Qs-Nd:YAG should be avoided. However, it is noteworthy that the settings for the laser used in this study are much higher than those used in other melasma studies.

Conclusion on Peels for Melasma

The literature supports the use of low-concentration TCA peels (up to 25%) for the treatment of epidermal melasma and mixed-type melasma more so than dermal melasma . Phenol peels were not studied for melasma. Studies on dermal melasma are lacking. What is needed are more split-face studies to address melasma in the same patient using two different modalities including split-face peel and laser studies.

Effectiveness of Chemical Peels for Treating Lentigines and Actinic Keratosis

Many patients present for the treatment of lentigines and ephelides . These lesions can be seen across a wide range of ethnicities. Lasers and peels are commonly used modalities.

Li and Yang (2b) [10] evaluated a Qs-Nd:YAG laser versus 35% TCA for the treatment of lentigines in an Asian population. This was a split-lesion study of 20 patients with 37 lentigines in which the medial half of the lesion was treated with a Qs-Nd:YAG laser, 532-nm, 2.4–2.6 J/cm2, 10 ns, 2 mm spot size and the lateral half was treated with 35% TCA until an even frost developed. Results were evaluated photographically by four investigators, and scored on a 5-point scale (1–5 with 5 being the best), comparing baseline photos to photos taken 6 months posttreatment. Results showed improvement with both modalities (4.16 for laser and 3.67 for TCA). However, 65% of lentigines responded better to Q-switched neodymium-doped yttrium-aluminum-garnet laser (Qs-Nd:YAG), 14% did better with TCA, and 21% were equal.

Raziee et al. (2b) [11] looked at cryotherapy versus 33% TCA in the treatment of lentigines on the dorsal surface of the hands in patients with phototypes II to IV. Thirty-three patients (2 men and 31 women) with at least 5 lentigines on each dorsal hand were treated with cryotherapy to lesions on one hand (cotton-tipped applicator for 3–5 s) versus 33% TCA to lentigines on the other hand (cotton-tipped applicator to a fine white frost). Patients were evaluated photographically at baseline and at 2 months. Eight patients did not complete the study. Results were judged by one attending dermatologist and two residents on a 4-point scale. No patient showed marked improvement (>75% change). Results of cryotherapy showed moderate (50–75%) improvement in phototype II (100%), phototype III (44%), and phototype IV (0). Results for the TCA group showed moderate (50–75%) improvement in phototype II (33%), phototype III (11%), and phototype IV (0). The main complication was post-inflammatory hyperpigmentation (PIH) seen in 40% of cryotherapy- and 44% of TCA-treated hands. The difference in PIH between the two groups was not statistically significant. Pain and length of healing was greater in the cryotherapy group with 84% of patients saying cryotherapy was more painful and 76% saying that TCA healed faster.

Holzer et al. (2c) [12] compared aminolevulinic acid + photodynamic therapy to 35% TCA in a split-face blinded study on patients with at least five actinic keratosis (AKs) per treatment side. Patients were enrolled and randomized to left- and right-sided treatments on identical anatomic areas such as the forehead or midface or scalp. Twenty-eight patients were enrolled, but 23 completed the study. Aminolevulinic acid (ALA) + photodynamic therapy (PDT) was performed by applying 5% ALA to the anatomic area being treated, occluded for 4 h, and then activated by red light (Waldman PDT 1200), 600–740 nm, 75 J/cm2 at an irradiance of 75 mW/cm2. The TCA group had a topical anesthetic applied for 30 min, degreased with 95% alcohol followed by TCA 35% to an end point of an “even pink white frosting.” Results showed a reduction in AKs with ALA+PDT (58%) compared to TCA (31.9%). At 12 months, the ALA+PDT group showed 73.7% complete clearance compared to the TCA group with 48.8% (p = 0.011). Pain was notably higher in the PDT group (7.5 on visual analog score) compared to TCA (5.1). However, non-permanent scarring was seen in the TCA group in 6 patients (21.4%).

Hantash BM et al. (2b) [13] performed a prospective study of three groups of patients with extensive sun damage or a history of non-melanoma skin cancer (NMSC). Patients were phototypes I to III, had extensive AKs, and no history of prior skin resurfacing within 5 years of the study. They were primed and post treated with tretinoin 0.05% cream and a sunscreen. Patients were randomized to a 5-fluorouracil (5-FU) group (n = 9), 30% TCA peel (n = 10), ablative carbon dioxide skin resurfacing (n = 8). The 5-FU group had to apply the 5-FU cream twice a day for 3 weeks, the TCA group had one peel at 30% TCA performed to the level of an even frost, and the ablative CO2 laser group underwent two passes of fully ablative laser resurfacing. Patients were followed up every 3 months for 24 months. Actinic keratosis recurrence was measured and the development of any NMSC was noted. Of note, all but three patients in this study had a history of a face or scalp NMSC. Results showed that all three groups had a statistically significant reduction in AKs, 5-FU (83%), TCA (89%), and CO2 (92%), with no adverse scarring or pigment alterations. While it was a small study size, the TCA group exhibited a greater reduction in NMSC risk (3.75–5.25-fold) compared to the other two groups (p < .001).

Conclusion on Peels for Photodamage and Actinic Keratosis

Comparing Qs-Nd:YAG to 35% TCA for lentigines showed almost equal results. For areas that did not resolve, retreating with TCA or laser is an acceptable option. However, the cost-effectiveness of the TCA exceeds that of the laser. Similarly, the cost of cryotherapy or TCA peels are both very low. The improvement seen in cryotherapy over TCA for lentigines may suggest that the TCA peel was not performed deep enough. However, it is a fine balance between eliminating the lentigo and risking permanent hypopigmentation with any modality.

The use of ALA+PDT for AKs warrants a large study to truly draw conclusions on outcome. Studies need to be done with the same concentration of TCA but applied to a slightly deeper level. The authors mention “descaling” AKs before applying the ALA but did not do the same prior to applying the TCA. Furthermore, a slightly deeper peel may have resulted in more impressive AK reduction.

Reduction in AKs was seen as being substantial in 3 groups using 5-FU, TCA, or CO2 laser resurfacing. Large studies should be conducted to see if the reduced risk of NMSC with TCA peels carries forward. However, patients found the TCA recovery to be easier than 5-FU and CO2. That makes TCA a very cost-effective tool.

Effectiveness of Chemical Peels for Treating Acne Scars

In 2002, Lee et al. (2b) [14] described the CROSS technique now widely utilized for the treatment of icepick scars in which high-concentration TCA is applied focally to isolated scars to create wounding and subsequent improvement. This is performed by using a sharpened wooden applicator stick or other similar tool to focally apply TCA to the scar including the deep track of scar tissue associated with icepick scars.

Dalpizzol et al. (2b) [15] looked at the treatment of icepick and boxcar scars in a split-face, non-randomized, single-blinded study of 15 patients, phototypes IV or lighter, using the CROSS technique with TCA or phenol. The skin was primed with 0.3% adapalene gel nightly for 15 days prior to the start of the peels. The left hemiface was treated with 88% phenol and the right hemiface with 90% TCA using the standard CROSS technique . The peels were repeated every 21 days for 4 sessions. Patients were assessed photographically and were asked to rate healing time and pain for each side. Prior to treatment, both sides showed similar scar scores on an acne scar grading scale (ECCA). After the treatments, both sides showed statistically significant improvement in scars compared to baseline (ECCA) but again, there was no statistically significant difference between the TCA or the phenol sides in regard to the degree of improvement. Patients rated the phenol side as more painful during the procedure. There was no significant difference in healing time between the two acids. The DLQI (dermatological quality of life index) score improved from a score of 6.7 to 3.3 (p < .05) after the treatments. Four patients developed hyperpigmentation (two with TCA, two with phenol), two patients developed hypochromia (TCA group), and two developed widening of the scars (TCA group).

Ramadan et al. (2b) [16] evaluated 20 patients, phototypes III and IV, in a split-face trial of 100% TCA CROSS technique to subcision in patients with rolling scars. Acne scar severity was measured on a 4-point scale from 1 (macular), 2 (mild atrophy), 3 (moderate) to 4 (severe). Patients were treated with CROSS 100% TCA on the left side of the face and subcision on the right (needle gauge was not mentioned). Patients were treated 1–3 times at 1–4-month intervals. All scars improved with both techniques but improved more with subcision than TCA (p = 0.001). Of note, there was a large difference in baseline scar sizes between the right (0.416 cm2) and left (0.182 cm2) sides of subjects.

Leheta et al. (2b) [17] compared percutaneous collagen induction (PCI) microneedling (1.5 mm) with 100% TCA CROSS technique in acne scars (rolling, boxcar, icepick), in 30 patients (27 completed the study), phototypes II to IV. Patients were randomized to either the PCI (five passes in four directions) or the TCA groups, primed with a topical retinoid and 4% hydroquinone for 2 weeks prior to treatment, and received four treatments at 4-week intervals. Results showed an improvement in the severity of acne scars in both groups (p < .001 for each group) but no statistically significant difference in improvement between the two groups. However, when looking at scar morphology, rolling scars did better with PCI while boxcar and icepick scars did better in the TCA group.

Nofal et al. (2b) [18] compared three modalities in patients with rolling, boxcar, and icepick scars . Patients were divided into 3 groups of 15 patients: intradermal platelet-rich plasma (PRP) , 100% TCA CROSS , and topical PRP + microneedling (PCI, 2 mm, 6 passes in 4 directions). Three sessions were performed at 2-week intervals. All patients had an improvement in their scars with no statistically significant difference between the groups as graded by the patients, a quartile grading system, and photographic assessment (blinded evaluation). The authors did not breakdown responses by scar morphology.

Agarwal et al. (2b) [19] looked at 70% TCA CROSS in rolling, icepick, and boxcar scars in 62 patients (53 completed the study). Patients received four sessions at 2-week intervals. Blinded reviewers evaluated photographs, and patients performed a self-assessment and patient satisfaction survey. Physician assessment showed that 66% of patients had >50% improvement (22.6% excellent and 43.4% good). Patients reported excellent improvement (11.3%) and good improvement (54.7%). No patient reported a poor response. Boxcar scars showed the most improvement as rated by physicians and patients .

Conclusion on Peels for Acne Scars

The CROSS technique , utilizing 88% phenol or 90% TCA, has been shown to be effective in the treatment of boxcar and icepick scars. The treatment of choice for rolling or valley scars remains subcision or PCI. Rolling scars tend to be wider and deep, requiring a treatment that promotes collagen building while not altering surface color or texture.

The shortcoming of these studies is the lack of a standardized acne scar scale across studies to allow for better comparisons of outcomes. Furthermore, larger studies are needed to look at scar morphology and treatment outcomes to better decipher which scars do better with different treatments.

Preoperative Evaluation

Since skin resurfacing procedures create controlled wounds in the skin, there are precautions taken with regard to selecting the correct patient, preparing the skin, and minimizing complications by obtaining a good medical and social history. Preoperatively, patients should be screened for medications, allergies, smoking, infections, and a history of any psychological or behavioral issues that may make them have unreasonable expectations or may make them less prone to following postoperative care. Patients that are pickers, for example, may pick at the unhealed skin and create infections or scars. Many studies talk about performing the procedure, but there have not been studies that objectively evaluate pre-resurfacing skin care, postoperative skin care, or the best regimen for viral and bacterial prophylaxis. Therefore, each study’s patient cohort is based on protocols selected by the investigators according to their personal experiences rather than being firmly grounded in science.

Most investigators suggest a pretreatment regimen of a topical retinoid (retinol, retinoic acid, retinaldehyde), a topical hydroquinone cream (2% or 4% applied daily or twice daily), and a sunblock. The pretreatment routine is usually started 2–6 weeks prior to the peel and resumed upon healing of the skin.

Antiviral Therapy

When the perioral area is being treated, physicians usually start an antiviral regimen starting the day before and continuing until fully healed, 7–14 days. The dosing of the antiviral regimen is physician dependent and may be adjusted if a patient has a strong history of herpes simplex virus (HSV) outbreaks. There is general agreement that antiviral therapy is mandatory for all patients undergoing perioral resurfacing since the risk of HSV becoming disseminated and causing scarring is catastrophic.

Antibacterial Therapy

There is no consensus on the use of antibiotics to prophylactically prevent infection. The infection rate with skin resurfacing is not high to begin with, but should an infection occur, the risk of scarring goes up. For this reason, care is taken to monitor these patients postoperatively in order to detect and treat infections early. No studies have been done to look at the rate of infection in patients treated or not treated with prophylactic antibiotics. The author has anecdotally found that mupirocin ointment applied to the opening of the nostrils three times a day starting 1 week prior to the peel and for 1 week afterwards results in a lower rate of postoperative bacterial infections .

Best Techniques and Performance

There is no consensus statement on properly performing this procedure. Most physicians will degrease the skin with acetone or 70% alcohol prior to the peel. The peel solution is applied with cotton-tipped applicator (CTA) sticks (TCA or phenol), a triangular makeup sponge (TCA), or two to three CTAs (phenol).

TCA Peels

Most physicians will degrease the skin with acetone or 70% alcohol prior to the peel. The peel solution is applied with cotton-tipped applicator (CTA) sticks (TCA or phenol) or a triangular shaped makeup sponge (TCA). About 2 min is allowed between applications to be able to see the full frost as it develops. If more depth of penetration is needed, more TCA is applied, and then the frost is re-evaluated. Frost is evaluated as mentioned earlier based on a level 1 to level 3 frost. As TCA is first applied, a light non-organized frost begins to form. This is a level 1 frost and signifies an epidermal level peel. Further application results in the frost being solid but with a diffuse pink background to become a level 2 frost. This marks a peel just reaching the papillary dermis level. Continued TCA application results in more solid white frost with a loss of the pink background indicating coagulation of the papillary dermis vascular plexus (level 3 frost). This is the deepest suggested level of application of TCA peels . Beyond this level, risk of scarring and hypopigmentation increases greatly.

Phenol Peel

Depending on the solution used and the extent of the peel, cardiac monitoring and intravenous (IV) hydration may be required. In instances of a half-face or full-face peel, the peel is performed in quadrants with a 15-min waiting time between application and lots of IV hydration to allow the body to metabolize and excrete any absorbed phenol. Great caution is indicated when performing a phenol peel on patients with impaired cardiac, hepatic, or renal function.

The skin is degreased with acetone. The phenol mixture must be swirled before dipping the CTA into it as the oil and water components have a tendency to separate. The solution is applied with 1–3 CTA (held like a fan). The skin quickly frosts when the solution is applied. The end point of a phenol peel is an even white frost. The frost quickly begins to dissipate so the physician must pay close attention to the treated area to avoid reapplying the solution and exceeding the desired depth of penetration .

Safety

There are no randomized clinical trials or large case series publications on the complications of chemical peels. Most publications report complications as they relate to the peels described in their study. In general, most peel complications stem from the depth of the peel and not from the actual solution used. Minor complications include post-procedure irritant or contact dermatitis to a product used for wound healing, acne flare up, swelling, erythema, sterile pustules, and PIH. Major complications include infection (viral, bacterial, fungal/yeast), hypertrophic/keloidal scarring, prolonged erythema, texture change, ocular injury from the solution, ectropion, and hypopigmentation. Early recognition and intervention is key to mitigating these complications.

Any suspected infection warrants a bacterial culture and sensitivity (aerobic, anaerobic, possibly mycobacterial) to identify the organism and to tailor antibiotics to the organism. The use of preoperative antibiotics that cover gram-positive bacteria may allow the growth of gram-negative bacteria by eliminating the normal flora balance. Infections typically are staphylococcus, but atypical mycobacteria, Enterobacter, Pseudomonas aeruginosa, and Escherichia coli have been reported.

Viral infections can present as areas that were healing and then began to regress. The virus can be herpes simplex or varicella zoster virus. Either of these can spread quickly on denuded skin and cause deep erosions and possible scarring. These viruses can erupt anywhere during the healing process until the skin is fully re-epithelialized. Cultures or direct immunofluorescence characterization of the virus should be performed, and high-dose (zoster dosing) antiviral medications should be implemented for 10 days and adjusted to clinical response.

With the occlusive dressings and use of antibiotics, patients can sometimes develop pruritic papules that show budding yeast on KOH prep. These usually develop by postoperative days 4 or 5. Oral anti-yeast agents can be helpful in treating this.

Postoperative Care and Follow-Up

There is no consensus on postoperative management . The extent of postoperative follow-up usually relates to procedure depth. “Lunchtime” peels may not require a follow-up necessarily. However, medium and deep peels should be followed up at day 3 or 4, again at day 7, and further out until the patient is fully re-epithelialized. Patients should be brought in at anytime if they call with any symptoms that portend scarring or infection.

Observations and Recommendations

Evidence-based summary: Grading of Recommendations Assessment, Development and Evaluation (GRADE )

Findings

GRADE score: quality of evidence

Chemical peels remain a very important tool in treating dyschromia , photodamage , and certain types of scars

D

With appropriate knowledge and training, physicians may find that they are able to treat a wider diversity of patients with peels as compared to laser resurfacing

D

Until larger studies are performed to standardize preoperative skin preparation, procedure performance, patient selection, postoperative management of complications, and indications, it behooves the physician to start slowly and gradually work his/her way up to deep peels

D

  1. PubMed Search: Chemical Peel Dyschromia, Chemical Peel Melasma, TCA Melasma, Phenol Melasma, TCA acne scars, CROSS TCA, CROSS peel, TCA peel

Self-Assessment Questions

  1. 1.

    A 53-year-old female, Fitzpatrick type III, Glogau type III, undergoes combination 30% TCA peel resurfacing of her face to a level 2 frost. She is at increased risk for all of the following except:

    1. (a)

      Post-inflammatory hyperpigmentation

    2. (b)

      Bacterial infection

    3. (c)

      Acne flare up

    4. (d)

      Textural abnormalities

    5. (e)

      Melasma flare up

  2. 2.

    On day 4, post-resurfacing, the patient presents with purulent drainage from the wound, some thick, honey-colored crusting, and a low-grade fever. The most likely infectious etiology is:

    1. (a)

      Staphylococcus aureus

    2. (b)

      Candida albicans

    3. (c)

      Pseudomonas aeruginosa

    4. (d)

      Herpes simplex virus

    5. (e)

      Contact dermatitis

  3. 3.

    In an attempt to minimize or avoid post-inflammatory hyperpigmentation (PIH) after a resurfacing procedure, it is appropriate to:

    1. (a)

      Begin hydroquinone in the immediate postoperative period

    2. (b)

      Wait until re-epithelialization is complete to begin hydroquinone

    3. (c)

      Wait until evidence of PIH manifests itself

    4. (d)

      Begin hydroquinone therapy 5–6 weeks postoperatively

  4. 4.

    A 40-year-old male, Fitzpatrick type II, is seeking treatment of shallow, small atrophic acne scars. All of the following would be appropriate treatment modalities except:

    1. (a)

      TCA peel to the level of the reticular dermis

    2. (b)

      A 1 min 70% glycolic acid peel

    3. (c)

      CROSS TCA technique

    4. (d)

      Fractionated CO2 laser resurfacing

  5. 5.

    When evaluating a patient for chemical skin resurfacing, many factors must be assessed. Which of the following is the least important:

    1. (a)

      the patient’s expectations of improvement

    2. (b)

      medical history

    3. (c)

      family history

    4. (d)

      pre-existing skin disease

    5. (e)

      history of keloids

Correct Answers

  1. 1.

    d: A level 2 frost should not reach the reticular dermis thus the risk of scarring or textural change with a level 2 frost peel is low.

  2. 2.

    a: The most common bacterial infection is staphylococcus aureus. However, on the setting of an infection while a patient is on an antibiotic that covers gram-positive bacteria, a gram-negative infection should be suspected.

  3. 3.

    b: Once the skin heals, reinstituting hydroquinone may help reduce PIH rather than if one were to start HQ once PIH has set in.

  4. 4.

    b: A 1 min 70% glycolic acid will not reach the dermis to a degree that will build collagen in shallow, atrophic, boxcar scars.

  5. 5.

    c: While everything is important in medical, social, and family history, the family history would yield the least helpful information. It is better to understand the patient’s state of mind, health history, tendency to scar, and the history of skin diseases that may worsen or affect wound healing.