Chemical peels are cost-effective and one of the most commonly used cosmetic treatments in clinical practice. Not only do they carry historical significance that dates back to ancient times, but they are also continuing to evolve and work well in conjunction with other in-clinic aesthetic treatments (Lee et al, 2019). Recent data, published by the Aesthetic Plastic Surgery Databank (2020), stated that over one million skin treatments, including chemical peels, were performed in 2020. Today, a plethora of peeling agents are available; however, for this article, the author will primarily refer to AlumierMD peels, as these are used in her clinical practice. Their peeling agents contain alpha hydroxy acids (AHAs), beta hydroxy acids (BHAs) (which are lipid-soluble) and retinol. AHAs include glycolic acid, lactic acid, citric acid, malic acid, tartaric acid and mandelic acid. Salicylic acid is a beta hydroxy acid. Not every acid treats the same condition. Certain ingredients are more effective at treating acne on the back, while others benefit other conditions on the body (AlumierMD, 2019).
Skin peels cause controlled wounding to the epidermis and/or the dermis, which decreases the skin's pH. The aim is to stimulate new tissue and get rid of old dead skin cells to improve skin tone and texture by revealing a smoother appearance and reducing irregularities. Traditionally, skin peels are classified as light (superficial), medium or deep, depending on the depth and penetration of the ingredients. Lighter peels exfoliate and cause injury to the epidermis, medium peels treat the papillary dermis and can penetrate the upper reticular dermis and deep peels treat the mid-reticular dermis. Both medium and deep peels cause protein coagulation and cell necrosis. The epidermis thickens, dermal volume increases and collagen is stimulated. The deeper the peel, the more downtime is required, and an increase in side effects, such as scarring, extreme sensitivity to ultraviolet light (UV) rays and pigment alterations, are possible. Therefore, a gradual process of peeling is imperative to avoid trauma to the skin. However, when performed regularly, the skin becomes familiar with the process (Dayal et al, 2016; Truchuelo et al, 2017).
Superficial and medium-depth peels
With minimal visible peeling, superficial and medium-depth skin peels require little to no downtime at all (Zakopoulou and Kontochristopoulos, 2006; Landau, 2008). They are a desirable treatment due to their safety and cost-effectiveness and are typically selected due to less risk of exacerbation of pigmentation, inflammation or irritation (Trivedi et al, 2017). Superficial and medium-depth peels are suited to all Fitzpatrick skin phototypes. The side effects and downtime depend on the specific ingredients and their concentration, as well as other skin factors. To prevent post-inflammatory hyperpigmentation (PIH) Fitzpatrick skin types V–VI are required to be pre-treated with a tyrosinase inhibitor for 2 weeks before receiving treatment (AlumierMD, 2019). Within the most recent literature, the most common noted peeling agents are salicylic acid, glycolic acid and Jessner solution.
A combined salicylic and lactic acid peel is a well-suited option for active acne patients
Other commonly used peels in aesthetic practice are solid carbon dioxide slush and trichloroacetic (O'Connor et al, 2018), which, when combined, work very well in treating patients with acne, photoageing and depressed scarring (Brody, 2016).
Peels and ingredients
To treat the back area, clinicians may wish to use a peel with lactic acid (AHA) and salicylic acid (BHA). For example, the author's preference is the AlumierMD back treatment, which contains 20% lactic acid and 10% salicylic acid. These peels are ideal for acne sufferers and those wishing to reduce scarring and hyperpigmentation. AHA is a water-soluble carboxylic acid that works on the desmosomes that enhance exfoliation and stimulate cell turnover. Due to its great bioavailability, this increases skin thickness by stimulating collagen and elastin in the skin. AHA requires neutralisation with a sodium bicarbonate solution, sodium hydroxide or ammonium salt (Fabbrocini et al, 2009; Sharad, 2013). Lactic acid is biosynthesised for cosmetic formulations and is known for its reduction in skin inflammation due to its larger molecular weight compared to other AHAs (O'Connor et al, 2018).
To treat the neck and décolleté area, the author uses a peel that is a half Jessner solution, containing 7% lactic acid, 7% salicylic acid and 7% resorcinol. Resorcinol is a phenol derivative that is known to exfoliate the skin and benefit those with acne due to its keratolytic action therapy (O'Connor et al, 2018). Therefore, due to its action, it is equally suitable as a back treatment. With this ingredient, an apparent frosting is noticed as a result of protein coagulation (O'Connor et al, 2018), which is typically seen as an endpoint alongside erythema. Most commonly, the patient should experience itching, a tingling sensation or warmth. The patient should not experience any pain or discomfort during the treatment.
Retinol is another key ingredient. It is a synthetic derivative of vitamin A that enhances collagen and is a gold standard anti-ageing ingredient that accelerates skin renewal. Retinoids also inhibit melanin transfer from melanocytes to skin cells and work very effectively with pigmentation-blocking products. Moreover, retinol works considerably well for acne-prone skin by reducing pore size, and it can be offered to the patient as a home skincare product. Some peels also contain fruit acids, for example, papain (found in papaya) and bromelain (found in pineapple). Bromelain is widely recognised for its anti-inflammatory, anti-microbial and fibrinolytic effects (Rathnavelu et al, 2016).
Recent literature highlights that the most common skin complaints on the body are acne on the back, hyperpigmentation on the legs, chest and arms and keratosis pilaris on the upper arms and thighs (Small et al, 2012). These will be discussed in further detail in the next sections.
» A full medical history needs to be taken, as patients with comorbidities are deemed to be at higher risk of complications. For example, cardiac, hepatic or renal disease, diabetes and immunosuppressed patients are all at greater risk of delayed wound healing, toxicity and infection «
Acne on the body
Acne can have a detrimental effect on a person's self-esteem and, in severe cases, can cause undesirable scarring. It is seen as a chronic inflammatory disease of the pilosebaceous unit and can last for many years (Nofal et al, 2018). A combined salicylic and lactic acid peel is a well-suited option for active acne patients due to its ability to reduce pore size and sebum, and it is an effective treatment for moderate comedonal and inflammatory acne. The controlled damage by the peel is considered to promote the absorption of other topical treatments, thus increasing their pharmacological effect. However, it is important to consider that chemical peels are not effective for those with severe or nodulocystic acne (Obagi, 2021).
Salicylic acid has strong keratolytic and comedolytic properties. This acid promotes desquamation of the upper lypophylic layers of the stratum corneum, resulting in superficial desquamation and skin rejuvenation. It is also known for its antibacterial and anti-inflammatory properties. The latest published literature suggest that clinical studies have shown its effectiveness in reducing inflammatory lesions in patients with active acne (Obagi, 2021). Treatment is considered successful if the patient is treated in three to six sessions with 2–4-week intervals (Obagi, 2021). Swinehart's (1992) study used 50% salicylic ointment paste, containing methyl salicylate and croton oil, which reported excellent results for comedonal acne (Swineheart, 1992). Compared with glycolic acid, a more recent study found that salicylic acid was far better at treating acne and scarring (Garg et al, 2009).
Hyperpigmentation on the body
Hyperpigmentation is equally debilitating and is a very common skin disorder seen in all Fitzpatrick type patients. Such disorders arise from the melanocytic system of the skin. In the epidermis, melanin pigment is formed in the melanocytes, which cause the pigmentation. Melanin synthesis is controlled by the pituitary gland and is influenced by intrinsic and extrinsic factors, namely, sunlight radiation and hormones, while hypopigmentation is caused by underlying conditions that inhibit melanin production.
All Fitzpatrick skin types have the same amount of melanocytes; however, it can vary depending on sun exposure (Khoo and Halim, 2016). Interestingly, patients with lighter skin are at a higher risk of skin pigmentation disorders, particularly those closest to the equator (Khoo and Halim, 2016). The area of the body most affected by sun exposure is the face, but it can also be seen on the hands and back. A weekly or bi-weekly superficial AHA peel is recommended, and the depth of penetration is dependant on the concentration and duration of the treatment. A patient's tolerance to the peel naturally develops over time, and, therefore, the time that the peel is left on can be increased. However, it is imperative to note that discomfort, erythema and endpoints such as frosting should still be considered. Salicylic acid has been proven to be beneficial for those with inflammation-induced hyperpigmentation. When applied with 4-week intervals, salicylic acid has been seen to significantly improve moderately photodamaged skin. In Asian and Mediterranean skin types, melasma, solar lentigines and seborrheic keratosis are particularly common (Khoo and Halim, 2016).
Keratosis on the body
According to the British Association of Dermatologists (2017), keratosis pilaris (KP) is a condition seen in half of the population, and it affects adolescents more commonly than adults. It is the result of a build-up of keratin in the hair follicles, which causes a blockage and presents as small dry bumps on the arms and thighs. While the cause is unknown, it is considered to be genetic. Keratosis is non-transmittable, but it can cause emotional stress in patients. A chemical peel containing salicylic acid and lactic acid is the best course of action for this condition, and it can certainly improve KP. However, this condition is incurable, so further treatment options should be discussed with a general practitioner (GP). On the other hand, actinic keratosis (AK) requires treatment with one or more medium-depth peel. This condition is a result of too much sun exposure, and it can be found on the face, lips, forearms, scalp, neck or the backs of hands (Khoo and Halim, 2016). Systemic literature research was carried out by Steeb et al 2021, and they found that further high-quality studies are necessary for the effectiveness of chemical peeling for those with AK.
Contraindications
It is important to consider that peeling should only be conducted on a maximum of 25% of the body at each time (Jackson, 2014). Body peels borrow knowledge from facial treatments. However, in comparison to the face, a chemical peel when applied to the body respects some differences. The skin on the body has fewer pilosebaceous units than that of the face and is far drier. As a consequence, it is at a far greater risk of complications. For example, if salicylic acid is overused, it can cause systemic toxicity and the patient could experience a varying degree of discomfort (Small et al, 2012). Therefore, careful consideration is required when selecting the correct peel, particularly when treating delicate areas, such as the neck and décolletage area. For the best therapeutic result, very superficial stratum corneum and superficial epidermis are the most suitable, such as lactic acid, which is known to hydrate the skin (Small et al, 2012).
The occupation and lifestyle of the patient need to be considered, as outdoor work and exercise require UV protection to be maximised and continued post-treatment. Smoking cessation for patients 1 week before and 6 months after a peel is also recommended (Arif, 2015). Pregnant patients should be made aware that chemical peels are not considered safe, particularly peels containing salicylic acid, as the structure is closely related to that of aspirin, which is linked to birth defects, miscarriage and bleeding complications (Arif, 2015). Therefore, this needs to be addressed during the initial consultation stage.
Appropriately documented evidence is necessary for consensual purposes and before and after photographs are important for comparison (O'Connor et al, 2018). Any history of allergy to peeling ingredients or isotretinoin usage within the previous 6 months should be identified. Additionally, peeling should not be applied to open wounds (O'Connor et al, 2018). A test spot is not required for an AlumierMD peel and remains a controversial subject in practices and thus is infrequently performed (Cortez et al, 2014). However, deeper peels require a spot test. Practitioners may carry out a spot test prior to a superficial to medium-depth peel on the upper forearm, especially if they feel that the patient is at risk of a reaction due to skin sensitivities that were highlighted during the consultation. Alternatively, the balancing solution, which acts as a degreaser, contains a very small percentage of lactic acid and is an effective way to check whether any reaction would occur.
Further considerations
The patient needs to be made aware that more than one treatment is needed to combat the signs of ageing and treat skin concerns (Truchuelo et al, 2017). Therefore, a consultation is recommended for any patient considering treatment. A full assessment is required to ascertain what goal the patient has in mind, with an emphasis on educating the patient around treatment expectations (O'Connor et al 2017). It is imperative to manage realistic patient expectations and have an in-depth knowledge of peel agents and how to administer them (Truchuelo et al, 2017). A full medical history needs to be taken, as patients with comorbidities are deemed to be at higher risk of complications. For example, cardiac, hepatic or renal disease, diabetes and immunosuppressed patients are all at greater risk of delayed wound healing, toxicity and infection (Jackson, 2014). Furthermore, any previous resurfacing procedures, herpes simplex infection, post-inflammatory hyperpigmentation, photosensitivity or abnormal scarring should be considered, as this can increase the risk of post-treatment complications (Rendon et al, 2010).
Post-treatment results and care
Post-treatment care is pertinent to promote healing and soothe the skin, and the same aftercare that follows treating the face is applied (Small et al, 2012). Avoiding direct sunlight is imperative until the skin has fully recovered and is recommended indefinitely for those who are receiving multiple treatments. The patient should be given written confirmation relating to aftercare, as well as guidance on what can be expected following the treatment (O'Connor et al, 2018). Typically, the patient will experience redness, tingling or burning for the first few hours, followed by some dryness and slight irritation for a few days.
Conclusion
Chemical peels are an asset to any clinic. It is important to note that good skincare is a slow, steady and consistent process. Although a standalone treatment can provide many benefits, when treating the body, specific skin concerns, such as hyperpigmentation, acne or keratosis pilaris, require a course of chemical peel treatments to enable results. However, more research into chemical peel treatments for AK is required, and treatment options should be discussed with a GP. As an aesthetic practitioner, it is imperative to educate patients on the duration of treatments and all associated risks should be highlighted. Selecting the right peel for the right skin condition at the right percentage is recommended to boost results and to avoid triggering any unwanted side effects. Similarly, a post-procedure kit must be offered to every patient, regardless of whether the patient has received a superficial or medium-depth peel, as this will minimise any complications. It is imperative to educate the patient on the use of a good skincare regimen, the benefits of other topical treatments, such as retinoids, and the stringent use of UV protection (O'Connor et al, 2018).
Key points
- There is literature to support the use of chemical peels in addressing a variety of common concerns, including acne, hyperpigmentation and keratosis pilaris on the body. However, the use of peels to treat actinic keratosis is very limited, so advice from a general practitioner (GP) is necessary
- Patient expectations need to be managed professionally and with a realistic approach
- The importance of indefinite use of sun protection factor (SPF) needs to be highlighted, particularly if the patient requires treatment for a skin concern
- Careful considerations need to be made when choosing the right patient for a peel, and they should only be conducted by an adequately trained professional.
CPD reflective questions
- Why do you think isotretinoin usage should be discussed before a skin peel treatment?
- What layer of the skin does a deep peel reach, and is it necessary to use anaesthesia for this peel?
- Would you recommend and conduct a test spot before administering a peel? Why?