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Chemical Skin Rejuvenation in Asians
Skin Resurfacing
42
V
Chemical Skin Rejuvenation in Asians Rie Yamashita
When chemical peels were originally introduced in Japan, they used strong agents such as phenol and trichloroacetic acid (TCA). However, because of the high incidence of hyperpigmentation and scarring, their use was considered unsuitable for Asian skin. The development of superficial to very superficial chemical peels using alpha hydroxy acids (AHAs) and Jessner’s solution has made chemical peels in the Asian countries more promising. Since it has been shown that glycolic acid is quite effective, with fewer incidences of adverse reactions even in Asians, it has become the most popular peeling agent in Japan. Jessner’s solution and beta hydroxy acid (BHA) (e.g., salicylic acid) are lipophilic and exert keratolytic actions. These chemicals have been shown to be very effective, primarily for the treatment of acne and the care of oily skin or skin with open pores. Despite the problems associated with TCA on the Asian skin, it can be used for skin rejuvenation and antiaging when an appropriate pretreatment protocol is followed and the optimal concentration is chosen. TCA can also be used for spot application on senile pigments, freckles, and acne. Skin peeling–induced adverse events have been reduced by the use of a pre- and postchemical peel skin care regimen. The skin peel’s rejuvenating effects
have efficiently increased, resulting in long-lasting effects. Chemical peels have now become one of the most important treatments in the skin care armamentarium for Asian patients. For chemical peels to be successful, it is important to examine the skin condition of each patient before peeling, understand the patient’s objectives and purpose for seeking treatment, and choose the method most suitable for each patient.
Classification of Chemical Peels by Penetration Depth Skin peels are classified according to their potency and ability to penetrate and destroy the skin layers, as follows: 1. Superficial peel: to the papillary dermis 2. Medium-depth peel: to the upper reticular dermis 3. Deep peel: to the midreticular dermis This classification was later expanded to the following four levels1: 1. Very superficial (exfoliation) 2. Superficial (epidermal) 387
CHEMICAL SKIN REJUVENATION IN ASIANS
3. Medium depth (papillary dermal) 4. Deep (reticular dermal)
Table 42-2. Henderson-Hasselback Equation pH = pKa +
Based on the Rubin and the Harold Classification,1,2 major peeling agents and methods that are applied to Asian skin are summarized according to the penetration depths (Table 42-1).
log [A–] [HA]
or HA =
1 ×C 1 + antilog (pH – pKA)
where C = original concentration of acid HA = free acid value From Coleman WP, Lawrence N: Skin resurfacing, Philadelphia, PA, 1998, Lippincott, pp 52-53.
Characteristics of Chemical Peeling Agents and Preparation of Peeling Solutions Although concentration is one of the factors that determines the penetration depth of AHA agents, the penetration depth of the agents is not dose dependent. The ratio of the concentration of free AHAs, which can penetrate through keratinocyte layers, to total AHA concentrations is defined as a bioavailable concentration. The value of this free acid concentration is an indicator of AHA effectiveness on skin peeling, which is determined by its pH value. Most commercially available chemical peeling agents do not clearly describe their components and content percentage in the insert. Thus when a commercially available AHA agent is used, it is desirable to first measure the pH of the solution. Next, the free acid value, which is actually the effective concentration of the agent, is calculated, and then the chemical peel is performed based on the calculated values using the Henderson-Hasselbach equation. The pKa value of glycolic acid is 3.83 at 25o C (Table 42-2).3 For successful chemical peeling to occur, it is recommended that the surgeon first examine one agent
and understand its chemical characteristic and properties, and then use it until a comfort level with its optimal condition has been achieved.
Glycolic Acid (Hydroxyacetic Acid) Preparation Two formulas are commercially available: 70% solution and crystal with 97% purity. The solution can be diluted with distilled water alone or a mixture of distilled water and propylene glycol. The author generally prepares the solution by adding sodium hyaluronic acid, glycerin, and hydroxycellulose into distilled water and then titrating this solution to the optimal pH with a sodium citrate buffer. However, it is also acceptable and easy to prepare the solution simply by diluting it with distilled water. Moreover, the gelatinlike semi-liquid solution can be prepared using xanthene gum. Because the effectiveness of glycolic acid is monitored by the changes in the peeled skin, the author uses a solution with a transparent base.
Table 42-1. Classification of Various Chemical Peeling Agents According to Penetrating Depth Type of Peel
Chemical Formula
Approximate Depth of Wound
Very superficial
Jessner’s solution 10% to 50% glycolic acid 10% trichloroacetic acid (TCA) Salicylic acid Azelaic acid Retinoic acid 10% to 25% TCA 50% to 70% glycolic acid 35% TCA + Jessner’s solution 35% TCA + 70% glycolic acid 30% to 45% TCA Baker-Gordon phenol formula 88% phenol ≥50% TCA
Stratum corneum
Superficial Medium depth
Deep
388
Stratum granulosum to the basal cell layer Papillary dermis
Upper reticular dermis
APPLICATION
Storage Because glycolic acid is not light sensitive, it can be stored in a regular clear bottle for 2 years.
Phenol (88%), 3 mL Croton oil, 3 drops Detergent, 8 drops Distilled water, 2 mL
Lactic Acid Preparation The original formula is a liquid with 85% concentration, and it can be diluted with distilled water. Lactic acid can be used alone or as a mixture with other peeling agents. Storage Although lactic acid is not particularly light sensitive, storage is recommended in a brown bottle for no more than 2 years.
Jessner’s Solution Preparation The solution is prepared as follows: Lesolucynol, 14 grams Salicylic acid, 14 grams Lactic acid, 14 grams The solution is mixed in 95% ethanol to make a total volume of 100 mL. Storage The Jessner’s solution is highly sensitive to light and air. Therefore the recommended storage is in an amber bottle at room temperature for no more than 2 years.
Salicylic Acid (BHA) Preparation Salicylic acid is a powder that can be solubilized in ethanol. Storage Salicylic acid can be stored in an amber bottle at room temperature for 2 years.
Trichloroacetic Acid (TCA) Preparation TCA is 100% crystal and is generally dissolved in distilled water. Although TCA can be dissolved in alcohols such as ethanol, TCA in alcohol solutions cannot penetrate into the skin. Storage TCA can be stored in a transparent plastic bottle at room temperature and remain stable for 2 years. Phenol (Coal Acid) Preparation Phenol is available as an 88% solution. Of the several formulas, the Baker-Gordon solution is the most widely used. It contains the following preparation:
Pharmacologic Actions of Peeling Agent Chemical peels remove aged skin and rejuvenate the skin by using a natural healing process. Glycolic acid facilitates the turnover of the epidermis by destroying the hemidesmosome in the lower keratinocyte layers and reducing the attachment among the keratinocytes.4 This event can be observed with an electron microscope.5 This effect is very specific only to glycolic acid, unlike other peeling agents whose main actions are liquefaction of the superficial epidermal layer. In addition, glycolic acid can stimulate the synthesis of dermal components such as collagen, elastin, and glycosaminoglycan to thicken the dermis.6,7 Furthermore, an inhibitory effect of glycolic acid on the melanin production of melanocytes has also been suggested.8 In addition, glycolic acid acts on sebaceous glands to remove sebaceous material and penetrates into enlarged skin pores to constrict them. Salicylic acid breaks down and liquefies the keratinocytes. On the other hand, TCA and phenol denature the proteins of the superficial epidermis, resulting in dermonecrosis of the tissue. This initiates the process of tissue regeneration, during which collagen synthesis is stimulated and the papillary layer of dermis is thickened. Phenol also causes depigmentation.
Application In the United States and Europe, chemical peels have been performed to rejuvenate aged skin. In Japan, however, superficial to very superficial chemical peels are used for the reduction of the oily component in oily skin, shrinkage of enlarged skin pores, and treatment of dry skin. Chemical peels are also used for the treatment of acne9,10 (Figures 42-1 to 42-3), photoaged skin (Figures 42-4 and 42-5), chloasma (Figures 42-6 and 42-7), acne scars, and rough skin induced by lichen planopilaris. It is important to choose the peeling agents and methods most suitable to each patient. The lipophilic Jessner’s solution and salicylic acid are very effective for the skin care of acne and oily skin. Because 389
CHEMICAL SKIN REJUVENATION IN ASIANS
A
B Figure 42-1 A, Before the peel. The patient was a 28-year-old female with acne vulgaris that has been ineffectively treated with other methods. B, After the peel.
A
B Figure 42-2 A, Before the peel. The patient was a 22-year-old female with acne vulgaris. B, 3 months after the peel. A total of four peels were performed with Jessner’s solution and glycolic acid. TCA was locally applied twice by spot application onto the area of pustule.
390
APPLICATION
A
B Figure 42-3 A, Before the peel. The patient was a 29-year-old female with acne vulgaris that has been ineffectively treated with other methods. B, After the peel.
A
B Figure 42-4 A, Before the peel. The patient was a 72-year-old female with photoaged skin. B, After the peel.
391
CHEMICAL SKIN REJUVENATION IN ASIANS
A
B Figure 42-5 A, Before the peel. The patient was a 47-year-old female with photoaged skin and scattered pigmentations. B, After the peel.
A
B Figure 42-6 A, Before the peel. The patient was a 45-year-old female with chloasma. B, After the peel.
A
B Figure 42-7 A, Before the peel. The patient was a 47-year-old female with chloasma. B, After the peel. 392
APPLICATION
A
B Figure 42-8 A, Before treatment. The patient was a 45-year-old female with chloasma. B, After treatment.
these agents produce more desquamation than glycolic acid, patients feel as though they have experienced “peeling.” Patients may be concerned about interruptions to their social lives because it usually takes 1 week for the desquamation to settle. Laser or light therapy is effective for patients with photoaged skin, specifically senile pigmentation and seborrheic keratosis. Positive effects can be realized very quickly. Thus the combined therapy of chemical peels with laser may be recommended. In other cases, a glycolic acid peel for the entire face with spot application of TCA may be performed. The combination therapy of a glycolic acid11-13 or lactic acid peel, retinoic acid and hydroquinine ointment, and oral medication with tranexiam acid and vitamins C and E can be very effective for the treatment of chloasma or age-induced stained skin (Figure 42-8). The author pretreats the post-acne scars with Jessner’s solution and then performs a glycolic acid peel for the entire face. Then the author locally applies TCA to the area surrounding the depression. Multiple sessions are required for optimal results. For severe acne scars, the author often performs various combination therapies of resurfacing with the Erbium YAG laser, TCA peels, and nonablative lasers such as the Cool Touch laser (Cool Touch, Inc., Roseville, CA) or the Cool Glide Xeo (Cutera, Inc., Brisbane, CA) (Figure 42-9). TCA has been used as a primary agent for medium-depth chemical peels. The peeled skin becomes white in
appearance. This phenomenon is called frosting. It induces dermal injury by protein denaturing and aggregation. If this phenomenon persists too long, cicatrization may occur. The severity of frosting indicates the penetration depth of TCA into the skin. This process is irreversible and cannot be neutralized after the agent has been applied to the skin and frosting has occurred.
Jessner’s solution and salicylic acid can produce a similar whitening appearance not by frosting but by a coating with residual degenerated alcohol remaining in the skin surface. Although the Obagi Peel (OMP, Inc., Long Beach, CA) (i.e., blue peeling) controls the penetration depth of the TCA solution for safe application, it sometimes requires anesthesia and causes long-lasting erythema. Thus this method is not well accepted in Japan, where limitations to daily life are not well tolerated. On the other hand, superficial to very superficial peels using glycolic acid, lactic acid, and salicylic acid have been the chemical peels of choice in Japan because of their safety and low cost.
When a peeling agent is applied to the skin, the patient generally feels itching and burning pain on the skin. If the patient feels excessive pain, then the agent should be immediately removed. Some conditions may cause deeper penetration and excessive pain, such as facial shaving or application of a facial pack before the peel, sunburn, allergic or atopic dermatosis, or the presence of subtle scars. 393
CHEMICAL SKIN REJUVENATION IN ASIANS
A
B Figure 42-9 A, Before treatment. The patient was a 29-year-old female with acne vulgaris. B, After the peel and laser treatment.
Chemical Peel Consultation The following issues should be thoroughly discussed with the patient before the procedure.: 1. Effects of the chemical peel and other treatments 2. Actual method, frequency of treatments, interval between treatments, and cost 3. Skin care before and after the treatment 4. Adverse reactions and possible remedies 5. Limitations of the treatment
Preparation and Pretreatment The patient should follow several restrictions before the chemical peel: 1. No facial shaving 2. No facial pack or face scrub for 1 day before peeling 394
3. No suntan or sunburn for 2 weeks before peeling 4. No other facial rejuvenation treatments (e.g., other chemical peels, laser treatment, electric or wax removal of hair) for 1 month before peeling A medical history regarding allergies, infectious disease (e.g., herpes labialis or contagious impetigo), autoimmune diseases, or oral and topical medications (e.g., steroids) is taken. These conditions may delay healing after the chemical peel. Patients with hay fever–induced dermatitis may suffer from excessive pain or develop deeper penetration of the peeling agents. The patient may have very small, undetectable scars in the skin. The peeling agent can penetrate deep into those scars, causing an unexpected worsening of the scar. The skin should be thoroughly examined to detect any scar. Petroleum jelly should be applied on the scar and the area should be covered with tape to avoid contact with the peeling agents.
ADVERSE REACTIONS
The pretreatment for peeling, or so-called “priming,” is a skincare regimen that can be done at home for 3 weeks before the treatment. Although the use of priming is controversial, it facilitates the absorption of the peeling agent by the skin and improves facial rejuvenation when administered properly. Certain lotions and gels containing AHAs, retinoic acid, hydroquinone, and kojic acid have been used. However, they all cause inflammatory reactions at higher concentrations and may even cause problems for the chemical peel. It is essential to properly educate the patient regarding the use of various pretreatment agents.
contain hyaluronic acid. In most cases, peels are performed on a 4-week cycle.. The concentrations and pH of the glycolic acid are determined each time the peel is performed.
Procedure
Adverse Reactions
Removal of Oil The author uses acetone. Because of its strong, irritating smell, the patient is asked to breathe through the mouth. Application of the Peeling Agents The author applies 20% or 30% glycolic acid for 8 to 10 minutes. Because the effect of glycolic acid is time dependent, a timer is used. The optimal concentration and pH of glycolic acid are determined before each peeling and is based on the patient’s medical history and skin condition. TCA or salicylic acid is applied locally to areas with pustules or acne by spot peeling with a cotton swab, and then the pus may be gently squeezed out after the skin has cooled. A solution of 15% to 30% TCA is locally applied to the area of senile pigmentation. Patients often complain of a tingling, itchy feeling or pain. If the patient experiences excessive pain, the peeling agents should be immediately and completely removed by thoroughly washing the face. Water and steroid-containing eye drops should be available to rinse the eye in case the solution accidentally spills into the eye. Removal of the Peeling Agents The peeling agents should be removed from the skin with purified water gauze. In the author’s hospital, application of the peeling agents is performed only by the medical doctors, but removal of the agents and cleaning can be performed by the nurses. Cooling Currently, the author’s practice provides relaxation with aromatherapy. The face is cooled with a chilled lavender-water gauze (100% pure oil is mixed in the purified water) for 5 minutes. It has an antiinflammatory effect. If the redness of the skin is too strong, the author adds another 5 minutes of cooling. Application of Moisturizing Agents and UltravioletShield Cream The author uses moisturizing agents that
The following adverse reactions have been reportedly induced by chemical peels: hyperpigmentation or depigmentation, erythema, herpes, bacterial or mycotic infection, cicatrization, allergic reaction, and intoxication.
The skin-reaction response to the chemical peel may differ among individuals and also according to the daily lifestyle and habits of each patient. Many patients may have expectations that are too high because of the influence of mass media. Therefore it is necessary for medical professionals to educate patients regarding the science of chemical peels.
Erythema In general, chemical peel–induced erythema disappears within 3 hours to 3 days. However, it may last for 1 month if a TCA peel has been performed. The patients should be told that this reaction is a temporary phenomenon. It is important to completely remove the peeling agents when the peel is completed. In the event that some hot areas remain, the face should be cooled with a cold water compress until the heat sensation disappears. Figure 42-10 shows the facial condition of a 36-year-old female patient who had a 10-minute glycolic acid peeling (30%, pH = 1.2) followed by 5 minutes of cooling with a cold water compress. The erythema shown in this figure disappeared the next evening.
Hyperpigmentation and Depigmentation Although both hyperpigmentation and depigmentation may occur after a chemical peel, hyperpigmentation is the most frequent adverse reaction in Japan. Hyperpigmentation occurs as a result of inflammation caused by deep penetration of the peeling agent. The contributing factors include: 1) poor selection of patients with a prior history of hyperpigmentation; 2) the effect on the strength of the chemical peeling agent (i.e., changes in the pH values); 3) poor choice of peeling agent and its application method 395
CHEMICAL SKIN REJUVENATION IN ASIANS
A
B Figure 42-10 A, Erythema in a 36-year-old female immediately after treatment with a glycolic acid peel. B, The erythema disappeared within 2 days. The photo was taken 1 month after the procedure.
or duration; 4) insufficient skin preparation before the application of the peeling agent; and 5) inadequate supervision during the skin changes after the application of the peeling agents. To reduce the hyperpigmentation, the following steps are recommended: 1. The patient’s skin condition should be examined before the peel. 2. The pH of the peeling agents should be measured. 3. A timer should be used to precisely monitor the duration of the application (Figure 42-11). 4. A standardized application method should be established. 5. The chemical peel should be performed in a bright room where the changes in the patient’s skin can be easily observed, and the face should not be covered. 6. Transparent peeling agents should be selected. 7. The treating physician should engage in a regular dialogue with the patient during the treatment to monitor how the patient feels. 396
Figure 42-11 A timer is used to measure the peeling time. Extra caution is required when the peeling agent is applied to the cheekbone, mouth angle, or nasolabial groove area because the peeling agents may penetrate deeper in these areas.
ADVERSE REACTIONS
Figure 42-12 Hyperpigmentation in a 32-year-old female after treatment with a glycolic acid peel.
A
The host factors for hyperpigmentation are as follows: 1) the patient used an aggressive facial scrub; 2) the patient is on medications with steroids; 3) the skin is dry; and 4) the patient is menstruating or did not have enough sleep. Figure 42-12 shows a 32-year-old female patient who was treated with a 40% glycolic acid peel at a pH of 1.5 for 8 minutes. She developed crust formation in the lower jaw area, which resulted in persistent hyperpigmentation. The application of a mixture of kojic acid, hydroquinone, and vitamin C may resolve the pigmentation. Unless the hyperpigmentation is very deep, the spots may disappear within 3 to 6 months in most cases. However, hyperpigmentation causes tremendous anxiety for the patient.
Temporary Aggravation of Acne Vulgaris Acne may become worse in 5 to 7 days after the chemical peel. This is usually temporary and easily improved with the use of antibiotics. When severe acne associated with hormonal imbalance (e.g., irregular menstruation) develops after the peel, then the patient should be comforted with a thorough explanation.
B Figure 42-13, A shows a 28-year-old female patient with severe acne even after various treatments, including a 5-year regimen of antibiotics. The photograph shows a worsening of the acne 10 days after a 5-minute salicylic acid (20%) peel followed by a 10-minute glycolic acid peel (20%, pH = 1.8). Her acne improved significantly within 1 week of antibiotic medication. Figure 42-13, B shows an improvement after five sessions of chemical peeling
Figure 42-13 A, Temporary aggravation of acne induced by a peel. The photograph shows a patient 10 days after the peel. A solution of 20% salicylic acid was first applied for 5 minutes, followed by a 10-minute treatment with 20% glycolic acid (pH = 1.8). The patient’s acne improved after a 1-week course of antibiotics. B, After five peels.
397
CHEMICAL SKIN REJUVENATION IN ASIANS
(5 minutes of 20% salicylic acid + 10 minutes of 20% glycolic acid [pH = 1.8]).
Herptic, Bacterial, and Mycotic Infections Severe bacterial infection is rare after a chemical peel. However, chemical peels are contraindicated in the patient with a history of herpes simplex or herpes zoster.
Cicatrization It is unlikely that superficial to very superficial peels cause cicatrization. The deeper a chemical peeling agent gets into the skin, the more effective it becomes. At the same time, the risk of adverse events becomes higher as the agent penetrates deeper. Therefore it is strongly recommended that deep chemical peels be performed by well-trained physicians or surgeons. Because deep peels using TCA or phenol have a higher risk of cicatrization, extra caution should be used for these treatments.
Figure 42-14 Incrustation 5 days after a chemical peel. The 22-year-old female patient had been treated with a 5-minute application of Jessner’s solution.
Allergy and Cardiac Toxicity The cardiac toxicity of phenol may cause severe arrhythmia or anaphylactic shock.14 Electrocardiograph monitoring is necessary during the procedure.
Intoxication Patients who use salicylic acid may exhibit symptoms of intoxication called salicylism. It usually begins with tinnitus and vertigo and may progress to anaphylactic shock when excessive doses are used. Lesolucynol, a component of the Jessner’s solution, may cause hypothyroidism when used as a long-term therapy. It also has hepatic toxicity and may cause a methemoglobinnemia-induced jaundice.
Incrustation Incrustation is always a strong concern among Japanese patients. Salicylic acid is notorious for producing crust
398
Figure 42-15 Incrustation 5 days after a chemical peel. The 58-year-old female patient had been treated with a 10-minute application of 30% glycolic acid (pH = 1.2).
formation. Therefore it is very important to educate the patient well and choose the correct peeling agents. Figure 42-14 shows a photo of a 22-year-old female patient 5 days after a 5-minute application of Jessner’s solution. She experienced incrustation that resembled a sunburn. In Figure 42-15, a 58-year-old female patient exhibited crust formation 5 days after a 10-minute peeling treatment with 30% glycolic acid (pH = 1.2). In Figure 42-16, a 52-year-old female patient exhibited crust formation 4 days after a 10minute peeling treatment with 40% glycolic acid (pH = 1.2).
ADVERSE REACTIONS
References
Figure 42-16 Incrustation 4 days after a chemical peel. The 52-year-old female patient had been treated with a 10-minute application of 40% glycolic acid (pH = 1.2). The crust peeled off spontaneously.
1. Rubin MG: Manual of chemical peels, Philadelphia, 1995, Lippincott. 2. Brody HJ: Chemical peeling, St Louis, 1992, Mosby, pp 1-5. 3. Yu RJ, Van Scott EJ: Biovailability of alpha-hydroxy-l acids in topical formulations, Cosmet Dermatol 9(6), 1996. 4. Smith WP: Comparative effectiveness of alpha-hydroxy acids on skin properties, Int J Cosmet Sci 18:75, 1996. 5. Fertash M, Teal J, Menon GK: Mode of action of glycolic acid on human stratum corneum: ultrastructural and functional evaluation of epidermal barrier, Arch Dermatol Res 289:404, 1997. 6. Moy LS, Peace S, Moy RL: Comparison of the effect of various chemical peeling agents in a mini-pig model, Dermatol Surg 22:429-432, 1996. 7. Moy LS, Howe K, Moy RL: Glycolic acid modulation of collagen production in human skin fibroblasts cultured in vitro, Dermal Surg 22:439-441,1996. 8. Moy LS, Mulad H, Moy RL: Superficial chemical peels. In Eheeland RG, ed: Cutaneous surgery, Philadelphia, 1994, Saunders, pp 463-478. 9. Wang C-M, Huang C-L, Sindy C-T, et al: The effect of glycolic acid on the treatment of acne in Asian skin, Dermatol Surg 23:23-29, 1997. 10. Yamashita R: Chemical peeling in the treatment of acne, Japan J Plast Reconstr Surg 46(3):271-278, 2003. 11. Yamashita R: Chemical peeling for photoaged skin pigmentation, Clin Dermatol 44(11):1207-1211, 2002. 12. Daniel P, Mary D, Steven H, et al: Short-contact 70% glycolic acid peels as a treatment for photodamaged skin, Dermatol Surg 22:449-452, 1996. 13. Joyce TEL, Siew NT: Glycolic acid peels in the treatment of melasma among asian women, Dermatol Surg 23:177-179, 1997. 14. Melvin S, Frank JG, Baron H: Complication of chemical face peeling, Plast Reconstr Surg 54:397-403, 1974.
399
42
V
Chemical Skin Rejuvenation in Asians Rie Yamashita
When chemical peels were originally introduced in Japan, they used strong agents such as phenol and trichloroacetic acid (TCA). However, because of the high incidence of hyperpigmentation and scarring, their use was considered unsuitable for Asian skin. The development of superficial to very superficial chemical peels using alpha hydroxy acids (AHAs) and Jessner’s solution has made chemical peels in the Asian countries more promising. Since it has been shown that glycolic acid is quite effective, with fewer incidences of adverse reactions even in Asians, it has become the most popular peeling agent in Japan. Jessner’s solution and beta hydroxy acid (BHA) (e.g., salicylic acid) are lipophilic and exert keratolytic actions. These chemicals have been shown to be very effective, primarily for the treatment of acne and the care of oily skin or skin with open pores. Despite the problems associated with TCA on the Asian skin, it can be used for skin rejuvenation and antiaging when an appropriate pretreatment protocol is followed and the optimal concentration is chosen. TCA can also be used for spot application on senile pigments, freckles, and acne. Skin peeling–induced adverse events have been reduced by the use of a pre- and postchemical peel skin care regimen. The skin peel’s rejuvenating effects
have efficiently increased, resulting in long-lasting effects. Chemical peels have now become one of the most important treatments in the skin care armamentarium for Asian patients. For chemical peels to be successful, it is important to examine the skin condition of each patient before peeling, understand the patient’s objectives and purpose for seeking treatment, and choose the method most suitable for each patient.
Classification of Chemical Peels by Penetration Depth Skin peels are classified according to their potency and ability to penetrate and destroy the skin layers, as follows: 1. Superficial peel: to the papillary dermis 2. Medium-depth peel: to the upper reticular dermis 3. Deep peel: to the midreticular dermis This classification was later expanded to the following four levels1: 1. Very superficial (exfoliation) 2. Superficial (epidermal) 387
CHEMICAL SKIN REJUVENATION IN ASIANS
3. Medium depth (papillary dermal) 4. Deep (reticular dermal)
Table 42-2. Henderson-Hasselback Equation pH = pKa +
Based on the Rubin and the Harold Classification,1,2 major peeling agents and methods that are applied to Asian skin are summarized according to the penetration depths (Table 42-1).
log [A–] [HA]
or HA =
1 ×C 1 + antilog (pH – pKA)
where C = original concentration of acid HA = free acid value From Coleman WP, Lawrence N: Skin resurfacing, Philadelphia, PA, 1998, Lippincott, pp 52-53.
Characteristics of Chemical Peeling Agents and Preparation of Peeling Solutions Although concentration is one of the factors that determines the penetration depth of AHA agents, the penetration depth of the agents is not dose dependent. The ratio of the concentration of free AHAs, which can penetrate through keratinocyte layers, to total AHA concentrations is defined as a bioavailable concentration. The value of this free acid concentration is an indicator of AHA effectiveness on skin peeling, which is determined by its pH value. Most commercially available chemical peeling agents do not clearly describe their components and content percentage in the insert. Thus when a commercially available AHA agent is used, it is desirable to first measure the pH of the solution. Next, the free acid value, which is actually the effective concentration of the agent, is calculated, and then the chemical peel is performed based on the calculated values using the Henderson-Hasselbach equation. The pKa value of glycolic acid is 3.83 at 25o C (Table 42-2).3 For successful chemical peeling to occur, it is recommended that the surgeon first examine one agent
and understand its chemical characteristic and properties, and then use it until a comfort level with its optimal condition has been achieved.
Glycolic Acid (Hydroxyacetic Acid) Preparation Two formulas are commercially available: 70% solution and crystal with 97% purity. The solution can be diluted with distilled water alone or a mixture of distilled water and propylene glycol. The author generally prepares the solution by adding sodium hyaluronic acid, glycerin, and hydroxycellulose into distilled water and then titrating this solution to the optimal pH with a sodium citrate buffer. However, it is also acceptable and easy to prepare the solution simply by diluting it with distilled water. Moreover, the gelatinlike semi-liquid solution can be prepared using xanthene gum. Because the effectiveness of glycolic acid is monitored by the changes in the peeled skin, the author uses a solution with a transparent base.
Table 42-1. Classification of Various Chemical Peeling Agents According to Penetrating Depth Type of Peel
Chemical Formula
Approximate Depth of Wound
Very superficial
Jessner’s solution 10% to 50% glycolic acid 10% trichloroacetic acid (TCA) Salicylic acid Azelaic acid Retinoic acid 10% to 25% TCA 50% to 70% glycolic acid 35% TCA + Jessner’s solution 35% TCA + 70% glycolic acid 30% to 45% TCA Baker-Gordon phenol formula 88% phenol ≥50% TCA
Stratum corneum
Superficial Medium depth
Deep
388
Stratum granulosum to the basal cell layer Papillary dermis
Upper reticular dermis
APPLICATION
Storage Because glycolic acid is not light sensitive, it can be stored in a regular clear bottle for 2 years.
Phenol (88%), 3 mL Croton oil, 3 drops Detergent, 8 drops Distilled water, 2 mL
Lactic Acid Preparation The original formula is a liquid with 85% concentration, and it can be diluted with distilled water. Lactic acid can be used alone or as a mixture with other peeling agents. Storage Although lactic acid is not particularly light sensitive, storage is recommended in a brown bottle for no more than 2 years.
Jessner’s Solution Preparation The solution is prepared as follows: Lesolucynol, 14 grams Salicylic acid, 14 grams Lactic acid, 14 grams The solution is mixed in 95% ethanol to make a total volume of 100 mL. Storage The Jessner’s solution is highly sensitive to light and air. Therefore the recommended storage is in an amber bottle at room temperature for no more than 2 years.
Salicylic Acid (BHA) Preparation Salicylic acid is a powder that can be solubilized in ethanol. Storage Salicylic acid can be stored in an amber bottle at room temperature for 2 years.
Trichloroacetic Acid (TCA) Preparation TCA is 100% crystal and is generally dissolved in distilled water. Although TCA can be dissolved in alcohols such as ethanol, TCA in alcohol solutions cannot penetrate into the skin. Storage TCA can be stored in a transparent plastic bottle at room temperature and remain stable for 2 years. Phenol (Coal Acid) Preparation Phenol is available as an 88% solution. Of the several formulas, the Baker-Gordon solution is the most widely used. It contains the following preparation:
Pharmacologic Actions of Peeling Agent Chemical peels remove aged skin and rejuvenate the skin by using a natural healing process. Glycolic acid facilitates the turnover of the epidermis by destroying the hemidesmosome in the lower keratinocyte layers and reducing the attachment among the keratinocytes.4 This event can be observed with an electron microscope.5 This effect is very specific only to glycolic acid, unlike other peeling agents whose main actions are liquefaction of the superficial epidermal layer. In addition, glycolic acid can stimulate the synthesis of dermal components such as collagen, elastin, and glycosaminoglycan to thicken the dermis.6,7 Furthermore, an inhibitory effect of glycolic acid on the melanin production of melanocytes has also been suggested.8 In addition, glycolic acid acts on sebaceous glands to remove sebaceous material and penetrates into enlarged skin pores to constrict them. Salicylic acid breaks down and liquefies the keratinocytes. On the other hand, TCA and phenol denature the proteins of the superficial epidermis, resulting in dermonecrosis of the tissue. This initiates the process of tissue regeneration, during which collagen synthesis is stimulated and the papillary layer of dermis is thickened. Phenol also causes depigmentation.
Application In the United States and Europe, chemical peels have been performed to rejuvenate aged skin. In Japan, however, superficial to very superficial chemical peels are used for the reduction of the oily component in oily skin, shrinkage of enlarged skin pores, and treatment of dry skin. Chemical peels are also used for the treatment of acne9,10 (Figures 42-1 to 42-3), photoaged skin (Figures 42-4 and 42-5), chloasma (Figures 42-6 and 42-7), acne scars, and rough skin induced by lichen planopilaris. It is important to choose the peeling agents and methods most suitable to each patient. The lipophilic Jessner’s solution and salicylic acid are very effective for the skin care of acne and oily skin. Because 389
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B Figure 42-1 A, Before the peel. The patient was a 28-year-old female with acne vulgaris that has been ineffectively treated with other methods. B, After the peel.
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B Figure 42-2 A, Before the peel. The patient was a 22-year-old female with acne vulgaris. B, 3 months after the peel. A total of four peels were performed with Jessner’s solution and glycolic acid. TCA was locally applied twice by spot application onto the area of pustule.
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APPLICATION
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B Figure 42-3 A, Before the peel. The patient was a 29-year-old female with acne vulgaris that has been ineffectively treated with other methods. B, After the peel.
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B Figure 42-4 A, Before the peel. The patient was a 72-year-old female with photoaged skin. B, After the peel.
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B Figure 42-5 A, Before the peel. The patient was a 47-year-old female with photoaged skin and scattered pigmentations. B, After the peel.
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B Figure 42-6 A, Before the peel. The patient was a 45-year-old female with chloasma. B, After the peel.
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B Figure 42-7 A, Before the peel. The patient was a 47-year-old female with chloasma. B, After the peel. 392
APPLICATION
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B Figure 42-8 A, Before treatment. The patient was a 45-year-old female with chloasma. B, After treatment.
these agents produce more desquamation than glycolic acid, patients feel as though they have experienced “peeling.” Patients may be concerned about interruptions to their social lives because it usually takes 1 week for the desquamation to settle. Laser or light therapy is effective for patients with photoaged skin, specifically senile pigmentation and seborrheic keratosis. Positive effects can be realized very quickly. Thus the combined therapy of chemical peels with laser may be recommended. In other cases, a glycolic acid peel for the entire face with spot application of TCA may be performed. The combination therapy of a glycolic acid11-13 or lactic acid peel, retinoic acid and hydroquinine ointment, and oral medication with tranexiam acid and vitamins C and E can be very effective for the treatment of chloasma or age-induced stained skin (Figure 42-8). The author pretreats the post-acne scars with Jessner’s solution and then performs a glycolic acid peel for the entire face. Then the author locally applies TCA to the area surrounding the depression. Multiple sessions are required for optimal results. For severe acne scars, the author often performs various combination therapies of resurfacing with the Erbium YAG laser, TCA peels, and nonablative lasers such as the Cool Touch laser (Cool Touch, Inc., Roseville, CA) or the Cool Glide Xeo (Cutera, Inc., Brisbane, CA) (Figure 42-9). TCA has been used as a primary agent for medium-depth chemical peels. The peeled skin becomes white in
appearance. This phenomenon is called frosting. It induces dermal injury by protein denaturing and aggregation. If this phenomenon persists too long, cicatrization may occur. The severity of frosting indicates the penetration depth of TCA into the skin. This process is irreversible and cannot be neutralized after the agent has been applied to the skin and frosting has occurred.
Jessner’s solution and salicylic acid can produce a similar whitening appearance not by frosting but by a coating with residual degenerated alcohol remaining in the skin surface. Although the Obagi Peel (OMP, Inc., Long Beach, CA) (i.e., blue peeling) controls the penetration depth of the TCA solution for safe application, it sometimes requires anesthesia and causes long-lasting erythema. Thus this method is not well accepted in Japan, where limitations to daily life are not well tolerated. On the other hand, superficial to very superficial peels using glycolic acid, lactic acid, and salicylic acid have been the chemical peels of choice in Japan because of their safety and low cost.
When a peeling agent is applied to the skin, the patient generally feels itching and burning pain on the skin. If the patient feels excessive pain, then the agent should be immediately removed. Some conditions may cause deeper penetration and excessive pain, such as facial shaving or application of a facial pack before the peel, sunburn, allergic or atopic dermatosis, or the presence of subtle scars. 393
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B Figure 42-9 A, Before treatment. The patient was a 29-year-old female with acne vulgaris. B, After the peel and laser treatment.
Chemical Peel Consultation The following issues should be thoroughly discussed with the patient before the procedure.: 1. Effects of the chemical peel and other treatments 2. Actual method, frequency of treatments, interval between treatments, and cost 3. Skin care before and after the treatment 4. Adverse reactions and possible remedies 5. Limitations of the treatment
Preparation and Pretreatment The patient should follow several restrictions before the chemical peel: 1. No facial shaving 2. No facial pack or face scrub for 1 day before peeling 394
3. No suntan or sunburn for 2 weeks before peeling 4. No other facial rejuvenation treatments (e.g., other chemical peels, laser treatment, electric or wax removal of hair) for 1 month before peeling A medical history regarding allergies, infectious disease (e.g., herpes labialis or contagious impetigo), autoimmune diseases, or oral and topical medications (e.g., steroids) is taken. These conditions may delay healing after the chemical peel. Patients with hay fever–induced dermatitis may suffer from excessive pain or develop deeper penetration of the peeling agents. The patient may have very small, undetectable scars in the skin. The peeling agent can penetrate deep into those scars, causing an unexpected worsening of the scar. The skin should be thoroughly examined to detect any scar. Petroleum jelly should be applied on the scar and the area should be covered with tape to avoid contact with the peeling agents.
ADVERSE REACTIONS
The pretreatment for peeling, or so-called “priming,” is a skincare regimen that can be done at home for 3 weeks before the treatment. Although the use of priming is controversial, it facilitates the absorption of the peeling agent by the skin and improves facial rejuvenation when administered properly. Certain lotions and gels containing AHAs, retinoic acid, hydroquinone, and kojic acid have been used. However, they all cause inflammatory reactions at higher concentrations and may even cause problems for the chemical peel. It is essential to properly educate the patient regarding the use of various pretreatment agents.
contain hyaluronic acid. In most cases, peels are performed on a 4-week cycle.. The concentrations and pH of the glycolic acid are determined each time the peel is performed.
Procedure
Adverse Reactions
Removal of Oil The author uses acetone. Because of its strong, irritating smell, the patient is asked to breathe through the mouth. Application of the Peeling Agents The author applies 20% or 30% glycolic acid for 8 to 10 minutes. Because the effect of glycolic acid is time dependent, a timer is used. The optimal concentration and pH of glycolic acid are determined before each peeling and is based on the patient’s medical history and skin condition. TCA or salicylic acid is applied locally to areas with pustules or acne by spot peeling with a cotton swab, and then the pus may be gently squeezed out after the skin has cooled. A solution of 15% to 30% TCA is locally applied to the area of senile pigmentation. Patients often complain of a tingling, itchy feeling or pain. If the patient experiences excessive pain, the peeling agents should be immediately and completely removed by thoroughly washing the face. Water and steroid-containing eye drops should be available to rinse the eye in case the solution accidentally spills into the eye. Removal of the Peeling Agents The peeling agents should be removed from the skin with purified water gauze. In the author’s hospital, application of the peeling agents is performed only by the medical doctors, but removal of the agents and cleaning can be performed by the nurses. Cooling Currently, the author’s practice provides relaxation with aromatherapy. The face is cooled with a chilled lavender-water gauze (100% pure oil is mixed in the purified water) for 5 minutes. It has an antiinflammatory effect. If the redness of the skin is too strong, the author adds another 5 minutes of cooling. Application of Moisturizing Agents and UltravioletShield Cream The author uses moisturizing agents that
The following adverse reactions have been reportedly induced by chemical peels: hyperpigmentation or depigmentation, erythema, herpes, bacterial or mycotic infection, cicatrization, allergic reaction, and intoxication.
The skin-reaction response to the chemical peel may differ among individuals and also according to the daily lifestyle and habits of each patient. Many patients may have expectations that are too high because of the influence of mass media. Therefore it is necessary for medical professionals to educate patients regarding the science of chemical peels.
Erythema In general, chemical peel–induced erythema disappears within 3 hours to 3 days. However, it may last for 1 month if a TCA peel has been performed. The patients should be told that this reaction is a temporary phenomenon. It is important to completely remove the peeling agents when the peel is completed. In the event that some hot areas remain, the face should be cooled with a cold water compress until the heat sensation disappears. Figure 42-10 shows the facial condition of a 36-year-old female patient who had a 10-minute glycolic acid peeling (30%, pH = 1.2) followed by 5 minutes of cooling with a cold water compress. The erythema shown in this figure disappeared the next evening.
Hyperpigmentation and Depigmentation Although both hyperpigmentation and depigmentation may occur after a chemical peel, hyperpigmentation is the most frequent adverse reaction in Japan. Hyperpigmentation occurs as a result of inflammation caused by deep penetration of the peeling agent. The contributing factors include: 1) poor selection of patients with a prior history of hyperpigmentation; 2) the effect on the strength of the chemical peeling agent (i.e., changes in the pH values); 3) poor choice of peeling agent and its application method 395
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B Figure 42-10 A, Erythema in a 36-year-old female immediately after treatment with a glycolic acid peel. B, The erythema disappeared within 2 days. The photo was taken 1 month after the procedure.
or duration; 4) insufficient skin preparation before the application of the peeling agent; and 5) inadequate supervision during the skin changes after the application of the peeling agents. To reduce the hyperpigmentation, the following steps are recommended: 1. The patient’s skin condition should be examined before the peel. 2. The pH of the peeling agents should be measured. 3. A timer should be used to precisely monitor the duration of the application (Figure 42-11). 4. A standardized application method should be established. 5. The chemical peel should be performed in a bright room where the changes in the patient’s skin can be easily observed, and the face should not be covered. 6. Transparent peeling agents should be selected. 7. The treating physician should engage in a regular dialogue with the patient during the treatment to monitor how the patient feels. 396
Figure 42-11 A timer is used to measure the peeling time. Extra caution is required when the peeling agent is applied to the cheekbone, mouth angle, or nasolabial groove area because the peeling agents may penetrate deeper in these areas.
ADVERSE REACTIONS
Figure 42-12 Hyperpigmentation in a 32-year-old female after treatment with a glycolic acid peel.
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The host factors for hyperpigmentation are as follows: 1) the patient used an aggressive facial scrub; 2) the patient is on medications with steroids; 3) the skin is dry; and 4) the patient is menstruating or did not have enough sleep. Figure 42-12 shows a 32-year-old female patient who was treated with a 40% glycolic acid peel at a pH of 1.5 for 8 minutes. She developed crust formation in the lower jaw area, which resulted in persistent hyperpigmentation. The application of a mixture of kojic acid, hydroquinone, and vitamin C may resolve the pigmentation. Unless the hyperpigmentation is very deep, the spots may disappear within 3 to 6 months in most cases. However, hyperpigmentation causes tremendous anxiety for the patient.
Temporary Aggravation of Acne Vulgaris Acne may become worse in 5 to 7 days after the chemical peel. This is usually temporary and easily improved with the use of antibiotics. When severe acne associated with hormonal imbalance (e.g., irregular menstruation) develops after the peel, then the patient should be comforted with a thorough explanation.
B Figure 42-13, A shows a 28-year-old female patient with severe acne even after various treatments, including a 5-year regimen of antibiotics. The photograph shows a worsening of the acne 10 days after a 5-minute salicylic acid (20%) peel followed by a 10-minute glycolic acid peel (20%, pH = 1.8). Her acne improved significantly within 1 week of antibiotic medication. Figure 42-13, B shows an improvement after five sessions of chemical peeling
Figure 42-13 A, Temporary aggravation of acne induced by a peel. The photograph shows a patient 10 days after the peel. A solution of 20% salicylic acid was first applied for 5 minutes, followed by a 10-minute treatment with 20% glycolic acid (pH = 1.8). The patient’s acne improved after a 1-week course of antibiotics. B, After five peels.
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(5 minutes of 20% salicylic acid + 10 minutes of 20% glycolic acid [pH = 1.8]).
Herptic, Bacterial, and Mycotic Infections Severe bacterial infection is rare after a chemical peel. However, chemical peels are contraindicated in the patient with a history of herpes simplex or herpes zoster.
Cicatrization It is unlikely that superficial to very superficial peels cause cicatrization. The deeper a chemical peeling agent gets into the skin, the more effective it becomes. At the same time, the risk of adverse events becomes higher as the agent penetrates deeper. Therefore it is strongly recommended that deep chemical peels be performed by well-trained physicians or surgeons. Because deep peels using TCA or phenol have a higher risk of cicatrization, extra caution should be used for these treatments.
Figure 42-14 Incrustation 5 days after a chemical peel. The 22-year-old female patient had been treated with a 5-minute application of Jessner’s solution.
Allergy and Cardiac Toxicity The cardiac toxicity of phenol may cause severe arrhythmia or anaphylactic shock.14 Electrocardiograph monitoring is necessary during the procedure.
Intoxication Patients who use salicylic acid may exhibit symptoms of intoxication called salicylism. It usually begins with tinnitus and vertigo and may progress to anaphylactic shock when excessive doses are used. Lesolucynol, a component of the Jessner’s solution, may cause hypothyroidism when used as a long-term therapy. It also has hepatic toxicity and may cause a methemoglobinnemia-induced jaundice.
Incrustation Incrustation is always a strong concern among Japanese patients. Salicylic acid is notorious for producing crust
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Figure 42-15 Incrustation 5 days after a chemical peel. The 58-year-old female patient had been treated with a 10-minute application of 30% glycolic acid (pH = 1.2).
formation. Therefore it is very important to educate the patient well and choose the correct peeling agents. Figure 42-14 shows a photo of a 22-year-old female patient 5 days after a 5-minute application of Jessner’s solution. She experienced incrustation that resembled a sunburn. In Figure 42-15, a 58-year-old female patient exhibited crust formation 5 days after a 10-minute peeling treatment with 30% glycolic acid (pH = 1.2). In Figure 42-16, a 52-year-old female patient exhibited crust formation 4 days after a 10minute peeling treatment with 40% glycolic acid (pH = 1.2).
ADVERSE REACTIONS
References
Figure 42-16 Incrustation 4 days after a chemical peel. The 52-year-old female patient had been treated with a 10-minute application of 40% glycolic acid (pH = 1.2). The crust peeled off spontaneously.
1. Rubin MG: Manual of chemical peels, Philadelphia, 1995, Lippincott. 2. Brody HJ: Chemical peeling, St Louis, 1992, Mosby, pp 1-5. 3. Yu RJ, Van Scott EJ: Biovailability of alpha-hydroxy-l acids in topical formulations, Cosmet Dermatol 9(6), 1996. 4. Smith WP: Comparative effectiveness of alpha-hydroxy acids on skin properties, Int J Cosmet Sci 18:75, 1996. 5. Fertash M, Teal J, Menon GK: Mode of action of glycolic acid on human stratum corneum: ultrastructural and functional evaluation of epidermal barrier, Arch Dermatol Res 289:404, 1997. 6. Moy LS, Peace S, Moy RL: Comparison of the effect of various chemical peeling agents in a mini-pig model, Dermatol Surg 22:429-432, 1996. 7. Moy LS, Howe K, Moy RL: Glycolic acid modulation of collagen production in human skin fibroblasts cultured in vitro, Dermal Surg 22:439-441,1996. 8. Moy LS, Mulad H, Moy RL: Superficial chemical peels. In Eheeland RG, ed: Cutaneous surgery, Philadelphia, 1994, Saunders, pp 463-478. 9. Wang C-M, Huang C-L, Sindy C-T, et al: The effect of glycolic acid on the treatment of acne in Asian skin, Dermatol Surg 23:23-29, 1997. 10. Yamashita R: Chemical peeling in the treatment of acne, Japan J Plast Reconstr Surg 46(3):271-278, 2003. 11. Yamashita R: Chemical peeling for photoaged skin pigmentation, Clin Dermatol 44(11):1207-1211, 2002. 12. Daniel P, Mary D, Steven H, et al: Short-contact 70% glycolic acid peels as a treatment for photodamaged skin, Dermatol Surg 22:449-452, 1996. 13. Joyce TEL, Siew NT: Glycolic acid peels in the treatment of melasma among asian women, Dermatol Surg 23:177-179, 1997. 14. Melvin S, Frank JG, Baron H: Complication of chemical face peeling, Plast Reconstr Surg 54:397-403, 1974.
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