Proprietary Peels

11 Proprietary Peels




Introduction


Chemical peels have evolved to encompass combination peel solutions or modifications of older, more traditional solutions. The impetus for these changes is to improve upon results while maintaining patient safety. As we will describe, the solutions have been modified to either enhance penetration or modified to slow down penetration; thus offering the physician varying degrees of control over the performance of the peel. In the age of lasers, chemical peels still play an extremely important role. If performed well, they can achieve results that equal or surpass much of the technology currently available.


Chemical peeling agents are classified as keratolytics or protein denaturants. Keratolytics (alpha-hydroxy acids, beta-hydroxy acids) are primarily used for superficial, exfoliative procedures whereas the protein denaturants (trichloroacetic acid (TCA) and phenol) can be used for superficial, medium-depth, and deeper peels. This chapter will focus on modified TCA and phenol peel solutions.


Peel depth is determined by multiple factors including the type of acid, acid concentration, volume of acid used, and skin thickness. Additionally, the duration and aggressiveness of skin preconditioning will also affect peel penetration. Skin preconditioning can help with peel penetration by thinning the stratum corneum or by decreasing oil (sebum) production. TCA is a water-soluble agent that does not penetrate well in sebaceous skin. Thus sebum control prior to peels helps to enhance peel penetration. Alternatively, phenol is lipid soluble however, as we will cover in this chapter, the croton oil in the phenol peel solutions may play a more important role in peel depth than the phenol concentration.


As with any resurfacing modality, proper patient selection is paramount. Patients should be evaluated for skin thickness, degree of oiliness, presence of inflammatory skin diseases (acne, rosacea), skin color, degree of skin fragility, and degree of skin versus muscle laxity. Medical and social histories need to inquire about medications that may impair wound healing, tobacco use, and the tendency towards herpes labialis infection.


Peel depth, no matter which modality used (TCA or phenol), should be selected to address the depth of the problem in the skin while not going so deep as to create pigmentary alteration or textural change.




Phenol peels


Phenol peels are categorized as deep peels. Similar to TCA, phenol works through protein denaturation and coagulation. However, phenol differs from TCA in that it penetrates quickly to the level of the reticular dermis. Phenol is partially detoxified by the liver and excreted through the kidneys. Percutaneous absorption of phenol can lead to rapid elevation of serum phenol levels, resulting in systemic toxicity and cardiac arrhythmias. Therefore, all patients should be cleared from a cardiac, hepatic, and renal standpoint preoperatively. In addition, intraoperative cardiac monitoring is imperative.


Phenol peels have in the past been primarily indicated for deep rhytides in older, fair-skinned individuals because of the risk for hypopigmentation. Although any resurfacing method that reaches the reticular dermis may cause permanent hypopigmentation, the traditional Baker–Gordon peel resulted in unacceptably high rates of hypopigmentation. Weaker solutions of phenol (25–50%) can be used to achieve lighter peels, however the results are no better than TCA peels and there is still the risk for systemic toxicity. Newer modifications of phenol peels with reduced levels of croton oil have significantly reduced the amount of postoperative hypopigmentation, post-operative erythema, and scarring. Both Hetter and Stone independently described modifications of phenol peels that allow better control over depth of penetration, allowing patients of a variety skin types to be treated. These newer formulations have contributed to a recent comeback of phenol peels, as they provide physicians with clinically and financially effective alternatives to CO2 and Erbium:YAG resurfacing.



Overview of Treatment Strategy



Modified trichloroacetic acid peels


Trichloroacetic acid (TCA) can be used to reach a variety of depths and is therefore considered the ‘workhorse’ of chemical peels. It acts by causing protein coagulation and denaturation of the cells in the epidermis and dermis as well as the blood vessels. TCA is self-neutralizing, meaning the peel will stop once it has coagulated a certain amount of protein. This is a key concept, because subsequent applications of TCA will drive the peel deeper, regardless of concentration, until the acid has coagulated proteins deeper down in the skin. Based on this knowledge, it is incorrect to refer to TCA peels as light or deep according to acid concentration.


There are four ways in which TCA can be formulated. To avoid errors in formulation, it is of utmost importance to purchase the acid from a reliable source using the weight to volume (W:V) method. The authors use a 30% TCA solution, which is then modified as part of the Obagi’s blue peel to create a 15%, 20% and 25 % solution.


In an attempt to obtain more consistent results while giving the physician more control over the peel, variations of the TCA peel (Monheit’s Jessner-TCA peel, Coleman’s glycolic acid-TCA peel, Obagi’s blue peel) have been developed (Table 11.1). Anatomically, they are designed to peel through the papillary dermis and into the most superficial aspect of the reticular dermis (Obagi’s blue peel). Their main indications are for epidermal and upper dermal pathology: photodamage, actinic keratoses, lentigines, ephelides, fine rhytides, and very superficial, non-fibrotic scars. Deeper cutaneous abnormalities such as expression lines, deep furrows, or deep scars are not amenable to correction with these peels.


Table 11.1 Summary of modified TCA peel solutions



















Modified TCA peels Peel components Speed of TCA peel
Jessner’s solution + TCA Jessner’s solutiona
Followed by the application of a light coat of 35% TCA
Stratum corneum is disrupted.
Faster TCA penetration
Glycolic acid + TCA 70% glycolic acid
Followed by the application of a light coat of 35% TCA
Stratum Corneum is disrupted.
Faster TCA penetration
Obagi’s blue peel Obagi’s blue peel baseb 2 mL
Mixed with a specific volume of 30% TCA to achieve 15%, 20% or 25% TCA-blue peel
Stratum corneum is left intact and a lower concentration of TCA is used.
TCA peel speed is slowed down

a Jessner’s solution: 14% resorcinol, 14% salicylic acid and 14% lactic acid mixed in ethanol


b Obagi’s blue peel base: non-ionic blue dye, glycerin, saponin


In an attempt to speed the penetration and depth of TCA peels, two modified peels were created which incorporate the use of a keratolytic agent. Monheit described a Jessner’s-TCA peel utilizing a keratolytic acid preparation, Jessner’s solution, applied prior to the application of TCA. Jessner’s solution is comprised of 14% each of resorcinol, salicylic acid, and lactic acid mixed in ethanol. Application of the Jessner’s solution allows for faster and deeper penetration of the subsequently applied 35% TCA. A similar mechanism is employed with Coleman’s glycolic acid-TCA peel, which uses 70% glycolic acid, also acting as a keratolytic, prior to application of 35% TCA.


The Obagi’s TCA blue peel is unique in that instead of increasing the speed and depth of the peel, the process is slowed down. This allows the physician better control of depth during the peel. The Obagi’s TCA-blue peel incorporates a non-ionic blue dye, glycerin, and a saponin with a specific volume of 30% TCA to yield a 15%, 20%, or higher percentage of TCA-blue peel solution. Traditionally, straight TCA is a colorless solution that requires close attention to avoid reapplication over previously treated areas. Part of the reason for incorporating a blue dye into the blue peel solution is to stain the stratum corneum thus helping the physician to visualize even application of the peel. The saponin is an emulsifying agent that creates a homogenous TCA-oil-water emulsion that penetrates the skin in a slower and more even fashion.



Modified phenol peels


For the most part, phenol peels fall into the category of deep peels. In a fashion similar to TCA, phenol exerts its actions by protein denaturation and coagulation; however it quickly penetrates the skin to the level of the reticular dermis. Thus, phenol peels are typically ‘quick’ peels with little time for adjusting the peel depth. There are a number of phenol peel solutions used historically with the Baker-Gordon formulation being the most recognized. Most solutions have phenol, water, croton oil, and either Septisol (Steris Corp., Mentor, OH), or other oils such as sesame seed or olive oil.


The Baker-Gordon formula resulted in impressive clinical outcomes but was fraught with about one year of postoperative erythema followed by permanent hypopigmentation. There was also a substantial risk of scarring or textural change. This limited the use of this solution to older, very fair-skinned patients.


Both Stone and Hetter evaluated the role of the different components in the various phenol solutions and they both came to the conclusion that the croton oil concentration was the most important factor in predicting the depth of skin injury (Table 11.2). Croton oil is a very strong desiccant with cytotoxic properties even in minute concentrations. Croton oil is not water-soluble but is soluble in alcohol, benzene, ethyl acetate, and chloroform. Thus it is believed that phenol, which has a benzene ring in its structure, acts as a carrier for the croton oil.


Table 11.2 Summary of various phenol-croton oil peel solutions

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Mar 12, 2016 | Posted by in General Surgery | Comments Off on Proprietary Peels

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