Chemical peels were initially used by nonmedical practitioners who used liquid phenol and croton oil as the key ingredients. In the 1960s, Thomas Baker, who was a physician, used a formula containing phenol, croton oil, water, and soap. It was found to be highly effective and reliable in treating severe wrinkles, but carried a high risk of hypopigmentation. It is thought that the reason for this is that the concentration of croton oil was too high. Chemical peels can be uncomfortable but in general are tolerated well with varying degrees of analgesia and the active ingredients are generally available.1–4
2. Baker TJ, Gordon HL. Chemical face peeling: an adjunct to surgical facelifting. South Med J 1963;56:412–414
3. Baker TJ, Gordon HL. Chemosurgery of the face: some warnings and misconceptions. J Fla Med Assoc 1962;49: 218–220
4. Baker TJ, Gordon HL, Seckinger DL. A second look at chemical face peeling. Plast Reconstr Surg 1966;37(6):487–493 PHENOL-BASED FACIAL PEELS 2. What is the main systemic risk to be aware of when using higher concentration phenol peels? Phenol has been used as a peeling agent for many years to provide a medium depth peel by the action of protein coagulation. It is, however, a high-risk agent to use, as it is rapidly absorbed through the skin and can lead to renal failure and liver toxicity. It has a direct action on the myocardium which can lead to cardiac arrhythmias. For this reason, patients undergoing a phenol peel require careful cardiac monitoring.1 To help minimize renal or cardiac toxicity, it is recommended to space peel applications at 10- to 15-minute intervals before applying a new coat in the same aesthetic subunit.2,3
5. Duffy DM. Avoiding complications with chemical peels. In: Rubin MG, ed. Chemical Peels (Procedures in Cosmetic Dermatology series). Amsterdam: Elsevier; 2006:137–170 The Fitzpatrick skin type classification describes the likely response to sun exposure with six grades and is most relevant to the risk of skin cancer development. It also describes the skin type/ethnicity of the patient ranging from white to brown and black skin types. It is relevant to both an aesthetic consult and one for potential skin cancer given the photoaging effects of UV light.1 Class I: Never tans, burns easily, fair skin Class II: Usually burns, tans minimally Class III: Burns moderately, tans moderately Class IV: Tans moderately and easily, burns minimally Class V: Rarely burns, dark brown skin Class VI: Never burns, dark brown, or black skin The Fitzpatrick classification of facial wrinkling is different and considers perioral and periorbital wrinkling with three classes based on depth of wrinkles and degree of elastosis. This may be a useful system more specifically for an aesthetic facial assessment.2 Fitzpatrick classification of facial wrinkling Class I: Fine wrinkles and mild elastosis Class II: Fine to moderate wrinkles and moderate elastosis Class III: Fine to deep wrinkles and severe elastosis The other descriptors (A, B, C, and E) form part of the Glogau classification, which can be used to describe features of photoaging. This contains four categories ranging from mild to severe. Each of these is linked to a typical age range and clinical findings that detail the degree of wrinkles, evidence of actinic sun damage, scarring, and makeup use. Patients are classified into age brackets according to the degree of photoaging. This too is applicable to the assessment of patients before facial rejuvenation.3
When considering chemical peels, it is important to evaluate the complete medical history of the patient including other recent treatments, regular medications, and a history of skin disease. Irrespective of their history, when undertaking a medium to deep peel, it is recommended that prophylactic antiviral medication is prescribed to minimize the risk of cold sore development posttreatment. If patients do still develop cold sores posttreatment while on antivirals, it is advisable to double the dose for a short period of time and arrange to see them early in clinic for review. Patients with history of skin diseases can be an increased risk of postprocedure complications including disease exacerbation, prolonged erythema, and/or healing. Patients with rosacea have a vasomotor instability and may develop an exaggerated inflammatory response after a chemical peel. There is no specific indication for oral antibiotics and if there is evidence of active infection that requires antibiotics, treatment should be postponed as this is an absolute contraindication to treatment. Oral nonsteroidal anti-inflammatory drugs (NSAIDs) are helpful for reducing posttreatment pain and swelling, but do not need to be prescribed pretreatment on a prophylactic basis. Oral antihistamines are not usually part of a chemical peel treatment plan either.1–3
During the pretreatment evaluation, it is important to identify the location, quantity, and depth of rhytids and the depth of any dyschromias evident. The benefit of using a Woods lamp is that it helps assess the depth of pigmentary changes. The worse the patient looks under a Woods lamp, the more superficial the pigmentation. This can help guide the appropriate treatment plan as to whether a more superficial or deeper peel should be used.1,2 The use of a Woods lamp has also been described during a superficial peel to help guide the actual treatment so that areas are not missed with the peel application.3 Assessment of the rhytids is predominantly clinical. The location and depth of them needs to be assessed as well whether they are static or dynamic in nature. Dynamic rhytids are best managed with an injectable neurotoxin and static rhytids can then be managed with either fillers or resurfacing with laser or a peel. It is vital to review your clinical findings and discuss them with the patient prior to the procedure. This helps balance realistic treatment expectations for both you and the patients. Be certain to point out gravitational change and skin excess that will not be corrected by chemical peels.
Use of a pretreatment regimen before performing a chemical peel is essential to prevent complications and optimize outcomes. A standard approach to the pretreatment regimen includes smoking cessation and minimizing sun exposure. A daily skin care program should include a buffing cleanser, an alpha hydroxy acid toner, and a vitamin A conditioner (retinoic acid 0.1%). Tretinoin is a synthetic retinoic acid that can stimulate collagen synthesis, exfoliate the stratum corneum, and increase glycosaminoglycan deposition. It does cause increased photosensitivity, so it must be used in conjunction with a sunscreen. It helps precondition the skin and should enhance the effect of the peel and speed epidermal healing.1–3 Tyrosinase inhibitors such as hydroquinone are indicated for use in patients with Fitzpatrick type III, IV, V, or VI skin or where patients have pigment dyschromias to reduce melanin production. This may prevent hyperpigmentation after the peel. Because this patient has pale skin and minimal pigment dyschromia, hydroquinone is not required. When it is used, hydroquinone can be used in 2 or 4% strengths, but the stronger version is available only on prescription. Hydroquinone 2% is sometimes used in combination with glycolic acid gel or kojic acid. A glycolic acid skin-conditioning program may be used 6–8 weeks prior to the peel to enhance overall results. Bupropion is an antidepressant medication that is used to treat both depressive disorders and help with smoking cessation by reducing cravings and withdrawal effects. Smoking cessation is important prior to undergoing a chemical peel but is not the mainstay of cessation therapy and would not be used as a skin preconditioner.
Superficial chemical peels tend not to cause much patient discomfort and are very well tolerated with little or no analgesia. However, with increasing peel depth comes more patient discomfort; so, anesthesia is often needed. Options include oral analgesics such as NSAIDs, acetaminophen, or opiates. Nerve blocks with local anesthetic can be useful to target the three divisions of the trigeminal nerve. Cooling the face with a fan can also be helpful. Unfortunately, topical agents may be best avoided as, although they can be effective for analgesia, they can induce vasoconstriction and thereby inadvertently increase the depth of a TCA peel. Where topical agents are being used during a TCA peel, it may be wise to reduce the peel strength to account for this. There is no evidence to suggest that topical anesthetic agents will affect the risk of dyschromia, bleeding, or allergic reactions. Their use will be complimentary to the use of NSAIDs.1,2
There are a number of factors which will influence the depth of a chemical peel. These include the agent used, the length of time the agent is in contact with the skin, the number of coats applied, and the pretreatment protocol used. In addition, the depth can be affected by the use of topical anesthetic agents, combining agents, and using occlusive dressings on the area during treatment. It is important to understand how each of these parameters impacts on a peel, as the provider needs to be able to gauge depth according to the desired results and acceptable posttreatment downtime and recovery. A superficial peel results in an epidermal injury, a medium peel results in a superficial dermal injury (papillary dermis), and a deep peel results in an injury into the deep dermis (reticular dermis).
TCA peels are useful for providing intermediate to deep peels, but in concentrations greater than 45% they risk irregular penetration and scarring. Their effectiveness can be optimized by careful skin preparation. This includes washing and degreasing the skin, mechanically removing surface debris, and applying three or four coats of Jessner’s solution. The endpoint for a TCA peel depends on the required depth and can be guided by the appearance of frosting. A pink-white frost suggests injury to the level of the papillary dermis, a dense white frost suggests injury to the superficial reticular dermis, and a dense gray/white frost suggests mid-reticular dermal injury (i.e., a deep peel). The series of changes during a TCA peel tends to follow the following course. An intermediate peel is a foggy white frost on an erythematous base. A second endpoint is an epidermal slide, which is produced if a cotton tip applicator is applied to the surface of the skin. This is also known as the accordion sign. When a deep peel is reached, the epidermal slide will disappear and be replaced by an intense gray-white or yellow blanch.1–3
Jessner’s solution includes resorcinol, salicylic acid, lactic acid, and ethanol. It does not contain TCA but is useful when combined with TCA for a medium depth peel. In its own right, it is also a useful peel agent that can provide superficial or intermediate depth treatments, depending on the number of coats applied. It works in a similar way to AHA peels as a keratolytic. A perceived benefit of using this for a chemical peel is that the combination of active agents means each one can be used with a decreased concentration and thereby reduce the risks of unwanted side effects.1,2
TCA is a derivative of acetic acid and is used for light, intermediate, and deeper peels. It is commonly used in concentrations between 15 and 50%. The problem with using it at the higher concentrations is that it can penetrate the skin in an irregular fashion and cause poor scarring. It is therefore best reserved for superficial and medium- depth peels and when doing so has a relatively short downtime with most of the skin sloughing occurring within a few days. Penetration depth can be improved by washing and cleansing the areas to be treated to remove oil and also mechanically removing surface debris. Chemically disrupting the skin surface barrier with mild acidic solution such as Jessner’s can also be helpful. TCA is not light sensitive and so does not need to be refrigerated. It remains stable for at least 23 weeks in an opened container. It is available in multiple different strengths and a 20% concentration can be used for epidermal and papillary dermal peel, with 25–35% concentrations used for upper reticular dermis (medium-depth) penetration.1–3
peels? AHAs are naturally occurring acids found in citrus fruits. They are used as superficial peel agents and cause exfoliation. They are available as over-the-counter preparations and prescription-only preparations, depending on their concentration and pH values. Higher concentrations of acid will provide a deeper peel. The FDA has limited AHAs for over-the counter sale to those of maximum 10% concentration (with a pH of >3.5), because more concentrated acids can cause epithelial necrosis instead of exfoliation. Therefore, the benefits of an office-based approach are that a higher concentration of acid may be used to achieve a greater response.1,2
Phenol and croton oil peels are used for achieving deeper peels. Phenol is a derivative of coal tar that causes rapid denaturation and coagulation of surface keratin. Phenol is effective for wrinkles and severe dyschromia and will penetrate to the mid-reticular dermis. Similar to TCA peels, the depth can be affected by skin preparation with washing and degreasing. Although deep chemical peeling over undermined skin (i.e., facelift) is not generally recommended, the chemical peeling of non-undermined areas is safe and effective. Therefore, use of this peel at the end of a facelift procedure would be entirely appropriate. The most common formulation is the Gordon Baker peel which includes 3 cc of phenol, 2 cc of tap water, 8 drops of liquid soap, and 3 drops of croton oil which is a skin irritant that causes inflammation, vesication (blister formation), and secondary collagen formation. When using this preparation to treat vertical perioral rhytids, a common concentration would be 33% phenol and 1.1% croton oil. This concentration is associated with acceptable side effects in Fitzpatrick I and II skin types. In contrast, a common concentration for the treatment of lower eyelid hyperpigmentation and fine lines is lower at 22% phenol and 1.1 % croton oil. Phenol does not affect hair growth; so, the preparation should actually be feathered into hair-bearing areas to ensure optimal blending when treating the forehead and temples. This would not, of course, be relevant to the perioral region. To help minimize renal or cardiac toxicity, it is recommended to space croton peel applications at 10–15 intervals before applying a new coat in the same aesthetic subunit; therefore, it will take longer than 10 minutes to perform this procedure.1–4