Peel: As the name implies, it is one of the important treatments in cosmetic dermatology by replacing the original imperfect skin with new skin. With the development of medical technology, it is now possible to treat skin diseases located in the superficial layers of the epidermis or dermis by controlled destruction of certain layers of the skin with chemical agents. Subsequent regeneration of the epidermis and reconstruction of the dermis can treat skin disorders located in the superficial layers of the epidermis or dermis, such as acne vulgaris, and is also indicated for all degrees of skin aging.
Chemical peels, also called chemical peels, are chemical agents that are applied to the surface of the skin, causing controlled destruction and peeling of the skin, promoting new skin regeneration and a more even distribution of melanin. When the peeling solution reaches the dermis, it will initiate the wound healing mechanism, causing the skin to rebuild and become smoother, thus chemical peels have anti-aging effects on the skin. Chemical peels have a long history, with early dermatologists using mainly phenols for peeling, which were widely used among Caucasians and only in recent years have they started to be applied among yellow Asians. According to the current stage of research on chemical peels, it is not only indicated for the treatment of diseases, but is increasingly used for purely cosmetic purposes.
Mechanism of action of chemical peeling.
1. Removal of excess stratum corneum by disrupting the interconnections between stratum corneum cells.
2. Partial destruction of the epidermal layer to promote epidermal cell turnover and dermal collagen regeneration. Since the skin is a whole and different cells interact with each other through cytokines, even if superficial peeling only destroys the epidermal cells, the structure of the epidermal and dermal papillae layers can be changed to some extent.
For example, hydroxyacetic acid, which is commonly used in superficial peels, not only penetrates into the dermis and directly accelerates collagen synthesis by fibroblasts, but also regulates matrix degradation and collagen production by stimulating the release of cytokines from keratin-forming cells. Interleukin (IL) is the main cytokine released by keratinocytes after hydroxyacetic acid treatment and is involved in regulating matrix degradation.
3. high concentration of peeling solution can lead to dermal necrosis and total skin loss. within 7 days keratin-forming cells of appendage origin migrate to replace the original epidermis: within 2-3 weeks dermal fibroblasts are activated. The number of collagen fibers and elastic fibers increases: and collagen rearrangement often lasts for about 6 months.
Depending on the depth of the chemical peel there are 3 types.
① superficial peels, which destroy mainly the epidermis and reach as deep as the papillary layer of the dermis.
②Medium peels, which can reach the upper dermal reticular layer;
Butler et al. compared the effects of superficial peels, medium peels and deep peels and found that the deeper the peel, the deeper the dermal improvement. This shows that deeper peels can achieve more pronounced anti-aging effects, but the probability of adverse reactions increases with the depth of the peel. Superficial peels are safer and have a shorter recovery time: the deeper the peel, the greater the adverse effects and the longer the recovery period.
Superficial peels are now gaining attention and are the most commonly used peeling procedure in clinical practice. It is effective for superficial skin diseases and mild skin aging; for deep wrinkles, scarring and more severe skin aging, medium or even deep peels are needed. However, for Oriental people. The latter two peels are prone to pigmentation abnormalities and are therefore less commonly used.
Fruit acids are natural organic acids that are widely found in nature and are mostly extracted from fruits, hence the name. The cosmetic benefits of fruit acids were first discovered and introduced to the dermatological community in the 1970s by Dr. Scott and Dr. Ruijin Yu, a Chinese-American physician. Nowadays, fruit acid peeling has become an important medical cosmetic tool, and it is easy to operate, has few adverse reactions, is safe and effective, and is increasingly accepted and favored by the public.
The concentration of fruit acids varies, and the skin level they act on varies. Low concentration of fruit acids acts on the epidermis, while high concentration of fruit acids can reach the dermis to achieve the purpose of peeling. Fruit acids have strong permeability, simple molecular structure, small molecular weight, and are easily absorbed by the skin. It has the ability to absorb water, which can increase the water content of the cells in the stratum corneum and improve the ductility of the stratum corneum. It can also penetrate into the dermis to increase the dermal papillae, increase the thickness, increase the mucopolysaccharide, increase the collagen fibers and increase the density of elastic fibers, thus increasing the thickness and elasticity of the dermis, directly accelerating the synthesis of collagen by fibroblasts, promoting collagen proliferation and increasing the production of natural moisturizing components of the skin. Therefore, it is a good moisturizer and can increase the water content of all layers of the skin.
For epidermis.
①Fruit acid regulates the degradation of the matrix by stimulating the release of cytokines from keratin-forming cells, reducing the adhesion of keratin-forming cells and keratin accumulation, allowing them to shed, removing excess keratin to correct the abnormally thickened stratum corneum, and achieving an anti-keratinizing effect that lasts up to 14 days after treatment, which is significantly different from other acids that only dissolve the most superficial layer of the stratum corneum of cells.
② activation of steroid sulfate esterase and serine protease to degrade the bridging particles and regulate the connection of the bridging particles of keratin-forming cells, which can achieve special effects and instantaneous exfoliation, regulate the process of keratin formation, increase the flexibility of the stratum corneum, and avoid excessive accumulation of the stratum corneum;
③Increases the layer of keratin-forming cells, increases the thickness of the epidermis, and has the function of moisturizing, restoring the skin barrier and anti-oxidation. It can remove the dead cells accumulated at the opening of sebaceous glands, so that the sebaceous glands can excrete smoothly, and the sebum, epidermal sweat gland fluid and water can form a sebaceous film on the outer surface of the skin through emulsification, which can protect the water inside the skin from evaporating too much and prevent bacteria from attacking the skin.
In addition, fruit acids can accelerate the metabolic rate of epidermal cells, reduce the content of melanin particles in basal cells, and have a therapeutic effect on some pigmented skin diseases; reduce the hyperkeratosis of hair follicle sebaceous gland ducts, so that the drainage of hair follicle funnel is smooth and sebum is excreted smoothly, preventing the accumulation of sebum and blocking pores, which can be used for the treatment of common acne; cause skin inflammation, and make the mast cells in the dermis degranulate. The medium released by mast cells can promote the proliferation of fibroblasts, thus forming rich collagen fibers, elastic fibers and matrix, so fruit acids have the effect of fighting skin aging and reducing wrinkles; superficial dermal capillary expansion skin circulation is improved and the overall skin quality is enhanced.
The low concentration of fruit acids can loosen the epidermis, improve photoaging, and treat skin diseases of epidermal hyperplasia and stratum corneum retention; the high concentration of fruit acids is a deep epidermal peeling agent that can change the appearance of the skin when applied to the skin to achieve “rejuvenation”, reduce acne, lighten hyperpigmentation, improve dry skin, and restore elasticity.
As a superficial peel, it is suitable for skin diseases located in the superficial layers of the epidermis or dermis. For example, acne vulgaris, chloasma, post-inflammatory hyperpigmentation, pseudofolliculitis of the beard, seborrheic keratosis, solar keratosis, freckles, enlarged pores, and mild skin scarring. Superficial peels are also suitable for preventing and delaying skin aging.
Contraindications to fruit acid peels: patients who are allergic to the chemical reagents to be used; patients with allergic dermatitis at the peel site; patients with bacterial or viral infectious skin diseases on the face (e.g. herpes simplex, common warts); patients with immunodeficiency diseases; patients who have taken oral retinoids within 6 months; patients who are taking oral anticoagulants or smokers and are not suitable for chemical peels because of slow skin healing; patients who have recently undergone surgery (with healing wounds); patients who have recently undergone radiation therapy.
Patients with insufficient protection against light or sunburn; those with a history of hypertrophic scarring or keloid; those who have undergone local cryotherapy within 6 months; pregnant women; those with a history of post-inflammatory hyperpigmentation or hypopigmentation (these patients are not absolute contraindications, but caution should be exercised and low strength peeling agents should be used. Shorten the peel time to avoid inflammation and the resulting risk of pigmentation abnormalities); mentally and emotionally unstable patients; and those who have undergone chemical peels within 2 weeks.
Pre-peel preparation: Pre-peel preparation is required before peeling. The prepared skin can produce a rapid and uniform frosting response compared to unprepared skin, which enhances tolerance, shortens the post-operative healing period and reduces the probability of adverse reactions. Fruit acids and retinoic acids, which contain gluconolactone/polyhydroxy acid (PHA) and lactic acid components, are the most commonly used prep ingredients. The former is mild but more expensive, while the latter is the opposite.
Precautions before peeling.
1. Use the following products every day for two weeks before peeling, not only to increase the adaptability of the skin, but also to make the peeling effect better; use low concentration (15%) of fruit acids and ointment prescribed by the doctor before going to bed, and use fruit acids and sunscreen lotion in the morning (KING YOUNG’s SPF16 or EUCERIN’s SPF25 is recommended; NEOSTRATA’s SPF60 enhanced sunscreen lotion is recommended for those with dark spots). If you have dark spots, we recommend using NEOSTRATA’s SPF60 sunscreen lotion), and again at noon. Patients with darker skin tone or those who want to improve dark spots or pigmentation.
2.No facial scrubs, hair dyeing or perming, waxing or shaving with razor blades, or sunburning the affected area within one week prior to treatment.
3. It is forbidden to shave with a razor on the day of treatment. After the initial peeling, there will be skin quality improvement effect, usually it takes 5-6 treatments to have the best effect.
Post-operative precautions.
1. If the skin feels normal after the treatment and only feels slightly tight or more sensitive, use two to four times a day with nutritional cream for one or two days. After the skin feels normal, you can resume the maintenance method before peeling.
2. If there is obvious inflammation (redness, pain) after treatment, in addition to applying two to four times a day nutritional cream, use anti-inflammatory cream to apply to the inflammation twice a day until the inflammation is eliminated. If there is a scab, do not pick the scab until it falls off to avoid scar formation. If there is redness, swelling or pus near the scab, please return to the clinic immediately for follow-up. After a few days, after the skin has completely recovered, you can continue to use the maintenance products you used before the peel.
3. The new skin after peeling is particularly sensitive to UV rays, so sun protection is very important. You must use sunscreen lotion every day, once in the morning and once at noon, and if you sweat a lot, you must replenish the sunscreen lotion more often, as well as sunbathe less and do a good job of physical sunscreen.
4. After the peel, you must suspend the use of fruit acids and skin care products used before the peel, and continue to use fruit acids and creams only after the skin is completely normal. Generally speaking, it takes about one to seven days.
Adverse reactions after peeling: Possible adverse reactions are hyperpigmentation or hypopigmentation, scarring. The higher the concentration of the peeling solution and the deeper the peel, the greater the probability of these adverse reactions. The probability of scarring from superficial peels is very small, while the appearance of hyperpigmentation is related to individual skin differences and is more common in Easterners and rare in Caucasians. Other adverse reactions include the appearance of milia, dilated capillaries, enlarged pores, persistent erythema, and increased sensitivity of the skin to wind, UV light, and temperature changes.
In conclusion, chemical peels are effective for treating acne, anti-aging, and eliminating wrinkles and discoloration, but require some skill. The operator has to develop a peeling program based on the patient’s needs, select the appropriate peeling agent, strictly control the peeling time, and make continuous adjustments throughout the procedure based on the patient’s response. The patient, on the other hand, should have the right expectations of the chemical peel, and should take care of the peel afterwards and take thorough sun protection measures to avoid hyperpigmentation. An experienced physician can only achieve the best results with chemical peels when the patient is very cooperative, so that the patient can truly have and maintain healthy, youthful skin.