The History of Chemical Peels

It is known from detailed notes on papyrus that medical personnel were using peels formulations to treat dermatological conditions in ancient Egypt as far back as 1550 BC. This was the period just before the coming of Rameses I when the Hysos kings ruled the great land, and it is documented that like today, skin physicians were in great demand amongst the more affluent women as sun- damaged skin was a sign of lower rank in society. In those days, before Botox? and skin lasers, women used a variety of substances such as alabaster, oils and salt to improve the skin. Of interest is the fact that sour milk was highly valued as an exfoliant, most probably because it contained lactic acid, an alpha-hydroxy acid commonly used today. But time, like the sun in the sky, passes on and eventually, an Egyptian family from Luxor waged a fierce set of wars against the foreign Hysos kings and finally drove them out of Egypt forever.

Many years later, a copy of the formulations of these chemical skin cures was found between the legs of a mummy in the Assassif district of the Theben necropolis. The manuscript passed through many hands until it was eventually purchased by Edwin Smith in Luxor in 1862, and thereafter became known as the Ebers Papyrus? In Europe that year, Otto van Bismarck became premier of Prussia, dissolved parliament and started collecting taxes for a conflict that ended with the Franco- Prussian War. The war had Bismarck’s desired effect of unifying the southern Germanic states and unfortunately nearly cost the life of a young German army physician called Paul Gerson Unna. In 1871, despite serious injuries, he returned to the University of Heidelberg to continue his studies and eventually became one of Germany’s greatest dermatologists. In 1881, Unna opened the Dermatologikum private dermatological hospital in Hamburg and the following year, he described a chemical peel composed of resorcinol, salicylic acid, phenol and trichloroacetic acid that is still in use today. His controversial doctorate on the histology of the epidermis and was controversial and eventually published in 1876. In 1886 he proposed the use of ichthyol and resorcinol against skin diseases.

?The use of Phenol

Phenol was discovered in 1834 by Friedlieb Ferdinand Runge, who extracted it from coal tar. In 1841, the French chemist Auguste Laurent obtained phenol in pure form. The antiseptic properties of phenol were used by Sir Joseph Lister (1827– 1912) in his pioneering technique of antiseptic surgery. Lister decided that the wounds themselves had to be thoroughly cleaned. He then covered the wounds with a piece of rag or lint covered in phenol, or carbolic acid as he called it. The skin irritation caused by continual exposure to phenol eventually led to its use in 1903 by the chairman of New York University dermatology society as a peel for acne scarring.

In 1919, Paul Unna became professor of dermatology at the University of Hamburg. In 1927 he described a chronic disease of the skin with seborrhea of the scalp and of the areas in the face and trunk that are rich in sebaceous follicles. It became known as Unna’s disease. The phenol method of exfoliation continued to be used, and during World War I, its antiseptic properties were used for wound care, especially after the rising number of explosions burns to the face in the dirty trenches. It was during this period that a French physician called LaGasse noted the improved aesthetic outcome of wounds dressed in phenol bandages. It is not known whether any of these soldiers eventually died of cardiac toxicity, but we do know that after the war ended, his techniques were brought to America by his daughter Antoinette who then began a cosmetic practice in California The art of chemical peeling remained amongst these cosmetic practitioners until the early sixties when Litton and later, Baker and Gordon, presented patients that they had treated with some of these cosmetic formulations to their dermatological colleagues. The Baker- Gordon peel of about 50-55% phenol is still widely in use today. It is made by combining 3cc of 88% phenol, 2cc of distilled water, 2 drops of croton oil and 8 drops of Septisol. The croton oil and Septisol are added to allow deeper penetration and more absorption of the phenol. In 1966, Baker published results of its effect on 250 patients. Before we look at the different types of chemical peels, we should first establish what skin problems we are trying to alleviate. In general, most peels are used to reduce the effects of chronological ageing, sun damage, scarring or pigmentary changes. These conditions occur at different levels within the skin and the type of chemical used must reflect that. Some pigmentary problems such as melasma occur in the upper epidermis and can be treated with superficial peels while other defects such as perioral wrinkles around the lip may require a deep peel, such as phenol. Either way, these chemicals will tend to result in a more youthful, smoother, less blotchy or more even, textured skin. The cosmetic doctor must choose a peel that relates to a certain depth of injury to create a desired effect and individually balance this against potential toxicities and complications in each individual patient. In general, peels are divided into three categories: superficial, medium and deep. The type of peel a physician uses often also has a lot to do with his personal experience and whether he has had previous problems with the various agents.

Superficial Peeling Agents

When people talk about superficial peels, they generally mean AHA (Alpha- hydroxy acids) peels involving the use of fruit acids such as glycolic acid derived from cane sugar at concentrations of 50% or higher. These peels are generally used to clear the upper layer of the skin in comedonal acne, to remove fine lines and sometimes to improve dry, flaky skin. In general, there are five main fruit acids:

?·????????Glycolic acid peels ·????????Citric acid peels ·????????Lactic acid peels

·????????Tartaric acid peels ·????????Malic acid peels

? There is something deeply humbling when we realise that most of these agents have been around since medieval times. We know that the ancient Egyptians used lactic acid in sour milk to improve the effects of sun damage. Cleopatra is said to have used asses’ milk to bathe in. Asses’ milk was believed to have a beneficial effect on the body, and Napoleon’s sister is also reported to have used asses’ milk for her skin’s health care. It is known that tartaric acid from wine was popular with French ladies during the seventeenth century and if we look at the other acids – citric from lemons and limes, malic from apples – we soon get the emergent picture. These chemicals are generally safe to use, and their effect is time dependent. The milder concentrations (<10%) are often used in home kits, the medium (<25%) by beauty therapists and the higher amounts (<70%) by nurses and doctors. The use of another agent such as a pre-peel primer or MDA - microdermabrasion can be used to potentiate the effect of an AHA peel. In general, these type of AHA peels should be neutralised with an alkali after use, but because this reaction is slightly exothermic, many practitioners tend to wash them off after use. After they are applied, the skin tends to become red, slightly swollen, and painful. When you are applying the peel, some white patches may appear, signifying some epidermal-dermal separation and if this occurs, it will tend to heal within seven to ten days. In general, we do not want frosting to occur with this type of peel as this tends to signify that the peel is coagulating with albumin in the dermis, and it has gone down too far. AHA peels usually exfoliate for about a week and new skin grows back over the area within a few weeks. If another AHA peel is required, one should wait until the skin has fully recovered. It is also preferable to use some sun protection for a limited period after their use.

Medium-Depth Peels

Medium-depth peels are mostly used for fine lines, wrinkles, superficial scars, stretch marks and to rejuvenate skin. Because of the prolonged period of downtime of about five days and the need to protect the skin from wind and sun for some months afterwards, medium peels are mostly used now in patients that cannot be fully treated with IPL and others who are not bad enough to require Erbium YAG resurfacing. There is little doubt that some patients prefer them as they tend to give a smoother texture and a more immediate effect than three to five courses of more expensive IPL treatments. Although trichloroacetic acid (TCA) is the most used medium depth peeling agent, it can also be used in combination with glycolic acids to reduce the possibility of scarring and to decrease the possibility of hyperpigmentation. TCA is different than more superficial AHA type peels in that the technique is not time-dependent and the agent does not require further neutralisation. It also produces a frost or whitening of the skin, which is dependent on the concentration used.

?·????????Trichloroacetic acid (TCA)

This chemical may also be used at lower (5-15%) concentrations as a superficial-to-medium peeling agent. It is typically used as an intermediate-to- deep peeling agent in concentrations ranging from 20-50% and the depth of penetration is dose-dependent. This peel is very safe at lower concentrations but can reach varying levels of dosage; if not treated with caution, it can lead to scarring and other complications. Easy TCA is one of the most popular, safe, medium peels. It is manufactured in Spain and made up to 17.5% concentration. It develops an intense frosting that usually dissipates within about 15-30 minutes after application of a cooling post- peel cream that contains anti-inflammatories. The TCA solution dissolves keratin, coagulates skin proteins, and causes precipitation of salts. It is neutralised by tissue fluids. The skin remains red for about 5 days and then turns brown and sheds like a snakeskin on the 5th or 7th day. Some practitioners rub the skin to try and get the solution to penetrate to a deeper level. This peel is usually applied with a cotton bud or a sponge and can be redone every week until the desired effect is obtained. It is sometimes useful to apply Ane-Stop topical anaesthetic or Emla after the procedure to decrease any residual burning sensation and increase patient comfort. Re-epithelialisation of the skin is normally complete within 10-14 days. TCA 50% is seldom used because of a higher risk of scarring and the availability of the combination peels.

The Obagi Blue peel

? The Obagi Blue peel has become popular in both the US and Europe. It was originally developed by Dr Zein Obagi to be used in all skin types, because some skin types are prone to hyperpigmentation after peeling. Because of this, the Obagi Blue is performed in 4 different steps to prevent post inflammatory pigmentation. These stages are probably more relevant to the ethnic skin tones of New York Italians, African Americans, and Asians than they are to downtown Dublin. There is also the downside of having to endure a bluish tinge to your skin for some days post procedure. ·??????

??Jessner Peel

?This peel is more popular in the United States where it originated. However, historical events dictated that it was not formulated in Europe, as it discovered by Jewish dermatologist Max Jessner. In 1928, Jessner travelled to Buriat- Mongolia on an expedition to study syphilis and the effects of the anti-syphilitic drug Salvarsan. After he returned, the Nazi government removed his professorship, because of his Jewish background. As propaganda against Jews increased, he was forced to emigrate to Switzerland in 1934. Ten years later he settled in New York, where he experimented with mixing salicylic acid, lactic acid, and resorcinol (each at 14%) to make a new chemical peel. Some practitioners use an AHA peel to prepare the face prior to peeling. The proceduralist then waits for a light frost to appear before neutralising the AHA and BHA acids with water or an alkali. Like TCA peels, the face becomes slightly painful, and a fan may be used to lessen the discomfort. The Jessner’s peel frosting may take many hours to dissipate. Salicylic acid (from Latin salix, willow tree) is a lipophilic monohydroxy benzoic acid, a type of phenolic acid, and a beta hydroxy acid (BHA). This colourless crystalline organic acid is widely used in organic synthesis and functions as a plant hormone. It has been used for several decades to remove the outer layer of the skin and is used to treat warts, psoriasis, ringworm, dandruff, acne, and ichthyosis. It is found in medications, such as AcneSal 2% and Whitfield’s ointment at 4%. It can penetrate acne comedones better than other acids. The effects of the salicylate are like aspirin, in that it has an anti- inflammatory and anaesthetic effect, resulting in some decrease in the amount of redness and discomfort associated with chemical peels.

Deep Peels

Deep peels are usually done to improve moderate wrinkling of the skin. They are usually performed with 88% phenol as it provides a relatively deep and predictable injury to the dermis. Phenol is the hydroxylated form of benzene and when it is used at this full strength, it immediately coagulates the skin tissue and prevents further absorption. If phenol is diluted, a different reaction occurs with disulphide bonds in the dermis and deeper penetration of the skin is technically possible. This phenomenon becomes important if a patient’s skin ‘cracks’ or ‘tears’ during a peel because deeper wrinkles may then form as the diluted phenol can cause further skin lysis. We can also use this effect to our advantage as post- peel occlusion with a zinc oxide waterproof mask will deepen the level of the peel and the amount of time required to grow new skin. Full face phenol peels are more popular in Spain and the US than in Britain or Ireland, where they tend to be used in more local applications such as the upper lip or around the eyes. Phenol peels also may be performed in various formulations, such as pure phenol (88%) or phenol mixed with soap, water, croton oil or olive oil. The names of these formulations are:

?·????????Gradè ·????????Baker-Gordon ·????????Venner-Kellson ·????????Maschek-Truppman

The most popular phenol peel is the Baker-Gordon formulation as it produces the most dramatic results and is the most effective peeling agent currently used to smooth out moderate wrinkles. The solution contains phenol 88%, 2 ml water, 8 drops?of liquid?soap (Septisol) and 3?drops of?croton oil.?Because this formulation is quite dilute with irritants; it penetrates deeper than pure phenol and may permanently affect the ability of the skin to tan. This peel is like an Erbium YAG laser, in that it is reserved for the face as it can cause scarring of the neck, arms and legs. It also causes more discomfort than any of the other peels and often should be done under a regional block or general anaesthesia.

The extract above is taken from Dr Patrick Treacy's book?'The Evolution of Aesthetic Medicine'?to be published in Jan 2022.?Dr Patrick Treacy was awarded the ‘Top Aesthetic Practitioner in the World and 'Aesthetic Doctor of the Year’ UK (Las Vegas 2019. He is recognised as one of the most influential aesthetic practitioners in the world being named amongst the ‘Ultimate 100 Global Aesthetic Leaders’ (2019, 2018, 2017). His research has strongly influenced this specialist area. He has developed global protocols relating to dermal filler complications and wound healing, as well as pioneering techniques for HIV facial lipodystrophy facial end prostheses and radiosurgery venous thermocoagulation.?