As previously mentioned, the ancient Egyptians used salt, animal oils and alabaster to improve skin appearance. Sulphur, mustard and limestone were also used in olden days. Early in the 1900’s, MacKee administered phenol for treatment of acne scars. Gross practised phenol peeling in Los Angeles in the 1930’s. In 1941, Eller and Wolff reviewed various exfoliation regimes. These included the use of pumice on the skin as well as sulphur and resorcinol pastes.
In 1966, Urkov described methods using phenol. In the 1960’s, Ayres compared his results with those of Morash, citing histologies of trichloracetic acid (TCA) and phenol. Brown et al reported phenol formula, the histological changes it produced and its potential toxicity. In 1962, Litton and Baker published their respective nonsaponized and saponized formulas. The 1970’s and 1980’s saw further advancements in full-face phenol application or TCA peels in combination with dermabrasion.
The common underlying concept is to wound the skin for the exfoliation of damaged epidermis and dermis with remodelling of the tissue with new collagen and new epidermis. Materials used for chemical peeling are keratolytic or and coagulant agents. TCA (trichloracetic acid) and phenol in high concentrations promote lys of skin layers. Together with scab formation, exfoliation and parallel epidermis regeneration, reorganization, proliferation of collagen and elastin bundles take place, clinically translated into a newly restored skin with a younger appearance. The surface becomes smoother without fine wrinkles, with significant improvement of deep wrinkles and pigmentation. (Fig. 18 – 21)
Chemical peels can be divided into superficial, medium and deep peels. By altering the type of chemical, the constituents of the chemical solution, the concentration of the solution or the technique, various degrees of exfoliation can be achieved. Superficial peels are used to treat superficial keratosis or dyschromia. These various chemical modalities include 10% to 20% trichloracetic acid (TCA), 70% glycolic acid and Jessner’s solution. Medium depth peels are used to treat deeper pigmentation problems, deeper keratosis and fine wrinkling. These agents include full strength phenol and 35% TCA. The TCA peel can be potentiated with the addition of Jessner’s solution, carbon dioxide or glycolic acid. These potentiating agents act as additional irritants that increase the permeability of the epidermis and allow increased penetration of the peeling agent. Deep peels are indicated to treat deep wrinkles associated with photoaging and deep pigmentation problems.
Common Indications for Chemical Peel:
- Wrinkle / aging
- Scarring: post acne
- Actinic keratosis
- Large pores – Hamartomatous skin
Prepeel skin conditioning: Preparation of the skin with Retin-A (0.025%-0.05%) AHA (10-20%), Hydroquinone 4%, Kojic Acid 2%, vitamin C, topical antibiotics and accutane (10-20mg) have been fully explained in the chapter on laser resurfacing.
Fig. 18 – 21. The factors that effects the depth of the peel are the number of passes and duration of peeling, concentration and chemical characteristic of solution that has been used and the skin preconditioning program. Deep peel is not recommended for skin type IV, V and VI (People from the Middle East, Asian and African).
Materials for Chemical Peel: Currently used are the TCA or AHA, commercial products that are now in the market now such as Blue peel, PCA and modified 42% TCA. Generally a more superficial peel is advised in dark and black skinned patients. (Fig. 18 -21)
- Exfoliation: depth of penetration of TCA is superficial to the dermis and basilar membrane:
Glycolic acid: 40%
- Superficial peel: reaches stratum corneum down to the papillary dermis:
- Medium peel: reaches stratum corneum down to the upper reticular dermal zone: should be used with caution in skin type IV, V, VI :
- Deep peel: Penetrates stratum corneum down to the mid-reticular dermis. It is not recommended for skin type IV, V, VI
TCA: 50% or
Litton’s formula : 3ml phenol 88%
8 drops glycerin
3″ cotton oil
2ml distilled water
Four factors that affect the depth of the peel:
- Skin preconditioning program
- Number of passes and duration of peeling
- Concentration of solution during treatment
- Chemical characteristics of each solution to be used: keratolytic, coagulant or both
|Monitoring depth and clinical observations (Obagi’s classification):|
|Exfoliation only:||–||No frost|
|–||Misty or cloudy appearance|
|–||Healing time one to three days|
|Superficial peel :||–||Light pink frost|
|–||Defrosting time ten to twenty minutes|
|–||Healing period five to ten days|
|Medium peel:||–||Solid white frost|
|–||No epidermal sliding|
|–||Defrosting time twenty to thirty minutes|
|–||Healing period of ten to fourteen days|
|Deep peel:||–||Solid grey frost|
|–||Firm skin to feel|
|–||Defrosting time < fourty minutes|
|–||Healing period twelve to twenty days|
Peeling Procedure: (Obagi’s method)
- Skin is cleansed with alcohol.
- Intravenous sedation if necessary.
- Fan against the face.
- Emla is contraindicated because it may alter the skin uptake.
- The chemical peel or TCA solution is applied with a pair of 2×2-inch gauze sponges applied in a criss-cross direction without hard rubbing or abrasion. The TCA solution is applied gently to the entire face to achieve superficial peel. Repeated applications by waiting one to two minutes in between, were performed as needed to achieve the desired depth of penetration on each part of the face. Depth signs are observed. Feathering techniques are used at the jaw line extending onto the neck and behind the ear to prevent sharp demarcation lines. TCA application also extend to the hairline without postpeel hair loss. The entire procedure takes approximately twenty to thirty minutes per patient.
Immediate Postpeel Management:
- Minimize facial expressions: Avoid aggressive chewing and smiling in order to avoid scarring, cobblestoning, roughness and cracking.
- Preferrably, liquefied diet for five to seven days postpeel.
- Avoid scab picking, peeling or cracking.
- Avoid sun exposure or cosmetics.
- Gently wash the face twice daily with mild soap.
- Apply gauze compression soaked with vinegar (acetic acid 1-2%) or boric acid 1-2%, twice daily for two to three minutes and very gently rub the face with this wet compress for one minute to prevent thick scab building up.
- Minimize the use of moisturizer to allow the scab to dry.
- Avoid the use of topical steroids during first week. The use of topical steroids during the second week is permitted.
- Male patients allowed to shave in second week.
This was reviewed at the laser chapter. (p. 456)
Complication of Chemical Resurfacing:
- Complications (dyschromia, erythema, infection, scarring) have been fully explained in detail in the previous laser resurfacing chapter. However, scarring is the most feared complication in chemical peeling, it is obviously the result of poorly controlled medium and deep peels, which the author does not recommend in dark or black skinned patients. The jaw lines, upper lip and periorbital areas have the highest rates of scarring because of the facial movements. Ectropion is the result of unidentified pre-procedure eyelid laxity. One of the ways to prevent scarring is to keep the patient on a liquefied diet during the first five to seven days postpeeling to avoid mastication and mimicry. Small keloids, when detected early, resolve completely by topical and injected steroids.
- Cobblestoning, surface roughness or cracking: are not considered complications because they do not compromise final results. This is a transient problem resulting from excessive facial movement. All cases respond well to skin conditioning and moisturizers.
- Marblelization: This is a transient problem which occurs in patients with severe solar elastosis, due to uneven TCA uptake by degenerated elastin, usually resolved by skin conditioning or additional superficial TCA.
- Sharp demarcation line: This condition is improved with topical skin reconditioning and superficial TCA feathering peel.
- Ectropion: Usually responses well to topical steroid therapy and massage.
Chemical peel should be cautiously considered with caution for patients from the Middle East and Asia. Skin preconditioning and postconditioning programs are mandatory. It is advisable to be very selective and careful with the medium peel and definitely avoid deep peel in patients of skin type IV, V and VI, in order to avoid permanent dyschromias and the feared complication of scarring.