What are chemical peeling?
Chemical peeling (from the English word to peel) consists of the controlled removal of different layers of skin via the application, on the area of the skin to be treated, of different chemical substances (salicylic acid, retinoic acid, trichloroacetic acid, resorcin, phenol, etc.) which are able to separate the ties that keep the cells united. It is possible, by using peeling, to obtain a remodeled, rejuvenated, improved skin, through the renewal of its various components.
According to the strength of the chemical agent used we can achieve a superficial peeling (limited to removing the dead cells of the corneous layer), medium (with the removal of the vital cells of the epidermis as well), or deep (the peeling goes as far as the dermis).
Superficial peeling, via the removal of the corneous layer, makes the surface of the skin more luminous immediately; it has a greater smoothness and a more elastic tone. In this case it is a procedure with a superficial action (the corneous layer and the superficial epidermis) in which the post-peeling process is short. It can be repeated every 15-30 days in some forms of active acne, and in the light stages of photo-ageing, to integrate some suitable home therapies, personalized skin care and other outpatient methods.
Medium peeling treatments are able to act, not only on the epidermis and the corneous layer, but also on the superficial dermis creating significant architectural remodeling and the possible elimination of lesions like some keratoses, by normalizing the irregular distribution of the melanin pigment and significantly improving the fine wrinkling, with long-lasting results. In this case the post-operative period is more demanding and the healing period requires 7- 10 days.
Deep peeling treatments are able to act in depth producing remodeling effects on the dermis that are difficult to obtain, even with the most modern laser techniques. They act significantly on medium and deep wrinkling, with radical and permanent effects, but they are aggressive procedures which, taking into account some excellent results, submit the patient to a greater discomfort, they require longer healing periods and are burdened with more numerous complications. They are, therefore, reserved for cases of significant cutaneous ageing. Furthermore, only certain types of skin can be submitted to this type of procedure, which is carried out in the operating theatre.
Effects of chemical peeling
So, generally, the objective of the peeling treatment is to obtain an aesthetic and functional improvement of the skin and to create evident changes via multiple working mechanisms, such as the renewal of cells by removing the dead cells of the corneous layer, the elimination of damaged and decayed cells of the epidermis, which are replaced by normal epidermal cells with the improvement of lesions like keratoses and pigmentations, and by the inflammatory healing reaction with the production of new collagen fibres and connective tissue being activated (revitalization of the dermis).
The face is the main area where it is used, but it can also be used on the neck, décolleté, hands and all the areas of the body where you wish to obtain this effect.
After a peeling treatment the tissues that have been removed are regenerated and we witness a restoration of the skin’s integrity. As well as a smoother, more uniform and luminous skin, whose cellular architecture has been restructured, there is also an improvement in its fundamental parameters, like its PH and hydration. The benefits of peeling are transitory and therefore it is necessary to repeat the procedure periodically to make the improvements lasting.
In many cases, rather than undergo very aggressive procedures, it is advisable to have several superficial or medium peeling sessions in order to obtain excellent aesthetic lasting results, by a cumulative process, without the risk of having unwanted effects.
Improvements of chemical peeling
The improvement that can be obtained using peeling regards photo-ageing, skin texture, dyschromias, and other pigmented lesions, fine lines, acne lesions and above all scar tissues and other superficial scarring. Moreover, peeling treatments can sometimes modify the size of the pores, improve the relaxation of the skin and aesthetically hide stretch marks, but they are not able to improve deep wrinkles and scars, couperose or racial pigmentation.
It is not possible to estimate exactly the entity of these improvements since the quantitive and qualitative aspects of the response and the duration of the therapy which is necessary to obtain them depend, as always in medicine, on multiple factors: such as the initial blemishing and its gravity and capacity to evolve, the possible presence of other accompanying conditions, the age, individual reactivity of the patient, environmental conditions, diet and life-style.
Chemical peeling is often inserted into the context of corrective skin therapy in which it can be combined with other methods like biostimulation, the use of injectable fillers or the use of laser and pulsed light.
Substance of chemical peeling
The most commonly used substances to carry out peeling treatments are glycolic acid, mandelic acid, retinoic acid, pyruvic acid, salicylic acid, trichloroacetic acid, or various combinations of these (so-called mixed peelings). The various substances can be used in a sequence (so-called combined peelings). It is up to the specialist to establish the most suitable type of procedure, case by case, based on the diagnosis.
Glycolic acid is a compound which is present in nature and an extract of cane sugar. It is used at low concentrations as a cosmetic with a smoothing function and it is hence able to improve the luminosity of the skin. At high concentrations (30-70%) it causes the cells to detach and produces an actual peeling process. It is applied to the skin and left to act for a few minutes, according to what is required, after which it is neutralized. The treatment will be repeated after 7-15 days for the number of times (3-10) needed to obtain the desired effect.
Mandelic acid is a by-product of almonds and has the characteristic of acting rapidly without causing stinging or redness and is, therefore, suitable for sensitive and coloured skins. It is also a substance that does not induce photo-sensitivity and so can even be used in the summer with a certain safety. The treatments are carried out every 15-30 days until reaching the desired effect.
Retinoic acid is the active form of vitamin A and has an almost hormonal type of action on the skin. This is because there are specific receptors present in the cells for this substance, which is able to activate the cellular proliferation of all the components of the skin, resulting in an improvement in the skin and an increase in its vascularisation and tone. The peeling is carried out as an outpatient. The retinoic acid paste (yellow in colour) is applied and left to act for about 40-60 minutes. The great advantage of this formulation is that the depth of the peeling (from superficial to deep) can be adjusted according to the number of re-applications of the paste. Consequently the type and time of the healing process will be different (from a light exfoliation with the duration of a few days, to an actual renewal of the skin, with lengthier healing times.
Pyruvic acid: this substance has the characteristic of easily penetrating into the areas which are rich in lipids and is therefore particularly suitable to penetrate into the pilo-sebaceous follicle, the terrain for acne. Furthermore it has a rapid exfoliating action at the level of the epidermis and also has antimicrobial qualities that, for this reason, make it useable on acne in the active phase. The treatments are carried out at a distance of 30-45 days from each other.
Salicylic acid: this is a vegetable substance which has chemical analogies with the aspirin molecule and is equipped with a very powerful superficial action, with a significant exfoliation of the corneous layer and an intense stimulation of the epidermis. It is also endowed with antimicrobial properties and is therefore suitable for acne in the active phase. The peeling treatment is carried out every 30-45 days, but it is not suitable for those who are allergic to aspirin.
Trichloroacetic acid: this acid acts chemically on the cells of the skin’s surface and, according to its concentration, can produce medium or medium-deep peelings, with the elimination of the epidermis and the stimulation of the dermis. Since it has a powerful action, it is able to produce a complete exfoliation of the epidermis, with its subsequent re-epithelialization: a process that can require from 7-15 days. Generally, we tend to carry out a single significant peeling with this substance, rather than a series of repeated treatments.
Contraindications of chemical peeling
The contraindications for peeling treatments are obviously those involving a known allergic reaction to the exfoliating agent. Moreover, dermatological lesions in the area (like herpes, inflammatory lesions, wounds, sun-burn, aggressive shaving, irritating waxing etc.) are all good reasons to put off the treatment. Even very dark skins or Asiatic and African skins can be unsuitable due to their easy pigmenting.
In general, during the peeling session the patient will feel a burning sensation of a varying intensity, based on the type of agent used and on individual sensitivity. Subsequently there is a hot sensation, linked to the local vasodilation.
After the peeling there may be red areas or de-epithelialisation which in some cases causes small lesions with scabs which heal spontaneously in a few days. Although, only in rare cases, these lesions can assume a more serious nature, even reaching the characteristic of burns. There can also be adverse irritative or inflammatory local reactions, which are, in any case, always solvable spontaneously or with suitable therapy. In the days following the peeling, it is also possible for small reactive lesions to appear on the skin, or some small pimples, milia cysts or mild dermatitis. The acids may encourage an increase in the evaporation of the water, accentuating the sensation of dry skin which is typical of the first few days after the treatment.
Side effects of chemical peeling
The possible after-effects go from persistent reddening (which lasts for weeks, above-all after aggressive peelings), to hyper pigmentation (possible in the case of inadequate photo-screening in the days after the treatment) or scarring (extremely exceptional). In general, all the possible after-effects tend to disappear spontaneously in time.
The skin’s response to peeling is better and the side-effects are rarer or less significant if the skin has been prepared before the treatment, with an earlier skin check-up and the use of suitable cosmetics and medicines which are able to condition a uniform and controlled response to the treatment. During the days following the treatment, it is equally important to strictly avoid using products of any kind on the skin and to use only non scented moisturizing creams, to abstain from exposing oneself to the sun and sun-lamps and to use a sun-screen. You should not use abrasive products, with an alcohol base, should not scratch or rub the skin, pull off the dead skin or any scabs and avoid using make-up.