While chemical peels are not new to the field of dermatology, they have reemerged as a popular treatment modality. Carlos Wambier, MD, PhD, discussed the benefits of chemical peels, how to prevent complications, and a recent revolution in the formulation of deep chemical peels in an interview with The Dermatologist.
Dr Wambier is the director of cosmetic dermatology research with the department of dermatology at Alpert Medical School of Brown University, RI.
The Dermatologist: Could you describe why chemical peels are popular and what their benefits are for using peels?
Dr Wambier: Chemical peels are as old as dermatology. The dermatology pioneers in every country were using chemical peels. In the 1990s, they lost some favor as new technologies, lasers, and energy equipment were sold to dermatologists. After using these technologies for some years, dermatologists are going back to chemical peels because they want more results and to deliver them with minimal costs, high efficacy, and high patient satisfaction.
Since the Journal of the American Academy of Dermatology published the 2 CME articles in August of last year, there has been a burst of interest in chemical peels. Many dermatologists and residents are now requesting training in chemical peels, since unfortunately training was neglected by many academic institutions.
For treating actinic keratoses (AKs), the main benefit is that physicians control the procedure and know the endpoint. Most field therapies for AKs have to be applied by the patient at home over a long period of time. The patient can experience extra downtime, and sometimes they have to stop treatment because they are unable to tolerate the cream, such as fluorouracil (5-FU) or imiquimod. Cryotherapy or cryosurgery, other physician-controlled procedures, are extremely painful and the skin of the patients usually blisters, and are usually not used for field therapy.
Most chemical peel procedures can be completed in 5 minutes, and the patient does not usually blister, unless there is an adverse reaction. The epidermis is injured but remains dry, in its place. Once the new epidermis grows underneath, the injured epidermis detaches naturally. For actinic cheilitis, the deep chemical peel is virtually painless. When we apply the phenol and croton oil, it numbs the lips and the patient does not feel any important pain during the procedure.
Patients only have to apply a moisturizer and wait for it to heal. Thus, it is a more convenient procedure, and its efficacy is at least similar to the use of 5-FU at home for a long period of time.
The Dermatologist: What are your recommendations for ensuring a successful procedure and when to use a superficial or a deep peel?
Dr Wambier: Before a chemical peel, the patient is put on adapalene, tretinoin, or tazarotene. They stop the retinoids 3 days before the procedure to avoid irritation from the topical medications in the procedure day. We recommend patients use a moisturizer that has no scent, is hypoallergenic, and has no parabens or anything that can cause dermatitis or allergic contact dermatitis after the procedure while the skin heals. Afterwards, we reintroduce retinoids.
Throughout this whole process the patient always uses sunscreen to protect themselves. However, with deep chemical peels, we do not prescribe sunscreens because the skin barrier is so injured. About 7 to 10 days after a deep chemical peel, when the skin barrier is restored, patients can go back to using sunscreen.
Superficial peels are meant to promote healthier and thicker epidermis, and with each peel there is an acceleration of the natural healing response of the skin. For example, acne can take weeks to heal and sun damage months to disappear. But with a superficial peel, we can make acne and sun discoloration heal faster, as well as red scars from acne. The medium-depth peel is mostly used for AKs and some deep melanosis, such as freckles or brown spots.
Figure: Before and after a single phenol-croton oil chemical peel.
The deep chemical peel changes the full thickness of the skin. It is a really deep injury that removes the whole epidermis and most of the dermis. A patient with deep wrinkles, for example, will no longer have them after a deep peel. If a patient has many AKs, after a deep peel, they are gone.
The Dermatologist: What are some common complications that can come from chemical peels, and what are some important considerations for avoiding complications?
Dr Wambier: The main complication we always try to avoid during the deep chemical peel is cardiac arrhythmia. The chemicals, specifically croton oil, are known to cause corrected QT (QTc) prolongation. If the chemical peel is performed on a small area, such as the lips or around the mouth, this risk is decreased, but we are still very careful when selecting the right patient for a peel.
We screen patients for arrhythmia and for use of medications known to prolong QTc, such as antidepressants, antihypertensives, certain pain medications such as opioids, and antiemetics. We try to minimize the use of those medications in the operative day, and we will not do this procedure in someone with cardiac arrhythmia and those taking medications to address it.
In addition, we perform the procedure in a safe environment with monitoring so we see if any issues occur and can pause the procedure.
While rare, a patient can have an infection during the peel, which can completely change the results. We are very careful because a patient can develop a scar if they have an infection. We recommend a daily care routine, and we prescribe antibiotic therapy as soon as possible if they develop one. Patients are already on antivirals, such as valacyclovir, to prevent herpes reactivation. Personally, I see my patients every day after a deep peel for the first week. Many of my colleagues have a nurse call the patient, but I prefer to see them so if anything changes within each 24-hour period, I can start therapy or address it.
A very important consideration for ensuring optimal results of a deep chemical peel is the concentration of croton oil. Lower concentrations of croton oil are used for mild peels and higher concentrations for stronger peels. The highest concentration of croton oil is the same as the Baker-Gordon formula, which is 2.1% croton oil.
Some physicians are still using droppers to count drops of croton oil, which is a problem because droppers come in various sizes. The wrong size dropper can administer a very large amount of croton oil. For example, 3 drops with a large dropper can be twice the size of the recommended drop in the formula and could reach concentrations up to 4.2%, which is an extremely strong, deep peel that will scar the patient.
I advise everyone who is doing deep peels to use syringes to measure volume and avoid using droppers, by using standardized Hetter’s formulas. This way they can be precise on how much croton oil they are using.
Another important aspect is using the same croton oil from the same distributer. Different producers of croton oil have different strengths. For example, companies sell croton oil after the extraction of the active ingredients (diterpenes which are used for research). If a provider buys online, from Amazon or eBay, then they risk getting a batch of croton oil that is not active. If they change the distributer, based on where it is produced or which country it is from, they can completely change the results.
The Dermatologist: Have there been any new developments in chemical peels?
Dr Wambier: There was a very important and recent change to the emulsifier agent. For about 60 years, the emulsifier agent was Septisol (triclosan cleanser), which was a handwash soap. Since 2019, after the FDA banned triclosan, we no longer have access to that triclosan soap.
For the past 2 years, I have been studying a substitute for that triclosan soap. First, we thought of keeping the triclosan soap formula, just removing triclosan but discovered that this formulation, which was chosen just because it was by the sink of a plastic surgeon’s office was what created instability of the emulsion. Historically it was told that the triclosan soap was mixed to emulsify the ingredients. There is a product on the market called Novisol cleanser (sorbitan laurate cleanser), which is a mild facial cleanser. We have found this to be the perfect emulsifier agent for phenol-croton oil in water emulsions.
We use the same proportions that we used for triclosan soap, with the same ratio of phenol, croton oil, and water. This formula remains stable over many hours, which means physicians do not have to stir the ingredients so frequently as before, and the efficacy does not depend on the speed between the physician stirring the formula to applying it on the patient. For example, if a physician took 15 seconds to apply a formula with triclosan soap, the phenol and croton oil would concentrate at the bottom of the applicator and would make the peel much stronger, the same disruption of the emulsion stability happens with at “any soap out there”, such as chlorhexidine soaps, or baby shampoos.
Now, with the current sorbitan laurate cleanser, the formula is chemically stable, so the strength of the ingredients remains the same over many hours. The physician can apply at any speed and still achieve the same results. This was a very important achievement and the first results of our studies in pig models were published recently in the Journal of the American Academy of Dermatology and dermatologists and plastic surgeons already have gained much clinical experience with the current emulsion over the past two years, it is a new stable system and the physicians who were applying the unstable formula will start a new and safer learning curve.
I think we are starting to return to chemical peels in our specialty. Hopefully, we have more light and truth with research and data in the near future to motivate people to start using chemical peels for preventing cancer with field cancerization treatments, as well as other indications.