Chemical peels are one of the most commonly used cosmetic treatments as they are both effective and can have less down time than some other treatments. However if they are used inappropriately, there can be adverse effects. Practitioners should always complete the proper training in administering chemical peels as there are various factors that come into play including the evaluation of the patient’s skin and health, the selection of the chemical peel based on the patient’s skin type and the goal of treatment, and the pre-care and after-care for the peel.

Levels of Frosting

A chemical peel is actually a controlled wound to the skin to improve its appearance after the healing process. The process of destroying the epidermis and/or parts of the dermis results in dermal regeneration and renewal. The term “frosting” is used to describe the appearance of the skin after a chemical peel. Different levels can help determine whether the peel is mild or deep. Not all peels will result in frosting and the frosting is not always due to the depth of the peel (for example salicylic acid – see Types of Peels below).

Level 0 – Pink or erythematous skin

Level I – Scattered white speckling with background erythematous skin

Level II – Frosted skin with background erythema showing through

Level III – Enamel white skin, no erythema visible

The levels of frosting can vary depending on the type of peel. A superficial salicylic acid peel may result in a different frosting level than a superficial TCA peel.

Depth of Peels

The more superficial peels will only penetrate the epidermis, while medium-depth peels will reach the dermis. When the skin condition being treated only affects the epidermis, a superficial peel will usually be effective. Conditions only affecting the epidermis include mild acne and melasma. The depth of the peel is not necessarily determined only by the ingredients. The strength/concentration of the ingredient is an important factor in determining how it will affect the skin. For example a TCA 10% peel will be more superficial than a TCA 50% peel. It will have less of a chance of scarring and of injury to the skin.

One depth of peel is not necessarily better than the other – it depends on the patient’s skin type and what the practitioner is trying to accomplish. For example a lighter peel may effectively treat acne but will not be able to treat a deep scar.

Medium depth peels should not be used in patients with a Fitzpatrick skin type that is greater than IV. These patients have a higher risk of developing post-inflammatory hyperpigmentation.

• Very light peels: 10 to 20% TCA, low-potency glycolic and salicylic acid, and retinoic acid
• Light peels: 20 to 30% TCA, Jessner solution, and 40 to 70% glycolic acid
• Medium peels: combinations of 35% TCA with either Jessner’s solution or 70% glycolic acid
• Deep peels: greater than 50% TCA, croton oil-phenol combinations

Our compounding pharmacy offers higher strengths of TCA and glycolic acid but we do not make any phenol combinations.

Skin Type

When judging the depth of peel that can be used on a patient, one major consideration is the patient’s skin type. The Fitzpatrick skin type scale is commonly used and includes Types I-VI.

• Type I: very fair skin, blue eyes, freckles, and light hair. Skin burns with sun exposure and does not tan
• Type II: fair skin, hazel/green/blue eyes, and light hair. Can tan with difficulty, but frequently burns
• Type III: white skin, any eye, or hair color. Can tan gradually, mild burn sometimes with sun exposure
• Type IV: brown or Mediterranean skin, tan easily and do not routinely burn
• Type V: dark brown or Middle-eastern skin, tan very easily and infrequently burn
• Type VI: black skin, almost never burns and tans very easily

For some peels, a patient with Type IV-VI skin will be at a higher risk of developing hyperpigmentation. Deep chemical peels and even some medium depth peels should be avoided in these patients. Superficial peels can in most cases be safely used in patients with any skin type.

Type of Peel

Glycolic 20-70% – Glycolic acid peels must be neutralized with water, 10% bicarbonate solution, or a saline-dampened cloth. Studies have shown that water is sufficient for neutralizing glycolic acid peels up to 35%.

Salicylic 20-35% – Salicylic acid peels will self-neutralize within 3 minutes. Frosting from precipitation of salicylic acid crystals will be seen but this is not the same as frosting that occurs with higher depth peels. The crystals can not actually penetrate the skin. This is sometimes referred to as a “pseudo-frost.” This pseudo-frost can be removed with a wet cloth or by washing the face.

Trichloroacetic (TCA) 10-35% – TCA peels will self-neutralize within 3 minutes. Low concentrations cause speckling while higher concentrations will result in frosting. TCA penetrates slowly, so the practitioner must wait at least 5 minutes after application to assess frosting. This prevents over-application when the practitioner thinks that the peel is not having an effect.

Tretinoin – Tretinoin peels cause the least discomfort of these chemical peel formulations. These peels are sometimes left on for longer periods of time and are comparable to a facial mask in how they are applied. They do produce erythema after application.

Jessner’s – Jessner’s peels will self-neutralize with white speckling and erythema.

Trichloroacetic (TCA) 40-50% – TCA peels will self-neutralize, frosting peaks within 2 minutes generally.

As you can see from these common chemical peel ingredients and strengths – most chemical peels will self-neutralize. Neutralization is the process of using some other substance to eliminate the effects of the acid on the skin. Glycolic acid is one exception (in this list of ingredients) which does require neutralization or it will continue to affect the skin and create further injury.

Pre-Treatment

Sun protection before and after a chemical peel is essential. The practitioner will also sometimes recommend a treatment be applied to the face for a few weeks before a peel in order to prevent post-inflammatory hyperpigmentation. Certain products like retinoids or hydroquinone may be used to make sure the skin’s pigment is treated evenly. Retinoids should be stopped about 3 days before the treatment. Patients also should not be taking isotretinoin immediately before (6 months), during, or immediately after the peel.

A degreasing agent should be used to remove any residue or makeup prior to the peel. This agent may be isopropyl alcohol or another suitable agent.

Post-Treatment

The post-treatment plan is focused on promoting healing and reducing the chances of infection. Ice packs can be applied to reduce swelling. For the first three days, the skin should be gently cleansed followed by application of petrolatum or another product recommended by the doctor. The petrolatum should be applied regularly for the first week.

Herpes simplex virus: If a patient has a history of herpes simplex virus they should receive antiviral medication for 7 days post-procedure. This is often recommended for all patients receiving medium or deep peels regardless of history of HSV.

 Sun exposure: Until the initial healing process is finished the skin should be protected from sun exposure using physical barriers like a hat or avoiding sun exposure entirely. After the initial healing process the skin can be protected with sunscreen.

Redness: The initial redness after the peel will last for several days. If redness of the skin persists longer than the healing period it may be due to allergic or irritant contact dermatitis or over-penetration of the peel. This may require further treatment by the practitioner.

Pain relief: For pain relief, practitioners will often suggest using over-the-counter pain relief medications.

Chemical Peel Safety

It is important to consider multiple aspects of safety and efficacy when using chemical peels. While it is often advertised as a simple procedure and an entryway for patients interested in cosmetic treatments, it is not without risks. The skill and knowledge of the practitioner is essential to making the treatment effective for patients.