By removing dead skin cells and promoting cell regeneration, chemical skin peels and microdermabrasion combat the effects of aging, sun damage, acne, and hormonal disorders. These facial rejuvenation techniques make the skin smoother and softer, reduce pore size, even out the pigmentation, and diminish the appearance of wrinkles, fine lines, age spots, blemishes, acne scars, and other superficial scars.This article supplies the skinny on three popular types of superficial skin peels:

• Glycolic acid peels use solutions of glycolic acid, an alpha hydroxy acid derived from sugar cane that’s now made in
the laboratory. Depending on the patient’s tolerance, solution strength can be increased from 20% to 70% over the course of the series of peels. Concentrations up to 35% can be used by a licensed esthetician; use of higher concentrations must be physician-supervised.
• Salicylic acid peels use salicylic acid, a beta hydroxy acid. Salicylic acid solutions are self-limiting, making them much safer and easier to use than glycolic acid solutions for both patient and provider.
• Microdermabrasion (pictured at left) uses abrasion instead of chem­icals to remove dead skin cells.

Chemical peels have been used for years with good results. Microdermabrasion—a much newer treatment (it received FDA clearance in 1996)—also has documented benefits. The choice of which technique to use hinges mainly on the patient’s skin problem and preference.

Skin-deep anatomy
The epidermis—the skin’s outer layer—consists of four strata (except on the soles and palms). New skin cells form in the deepest layer, the stratum basale. In a process called keratinization, these cells migrate through successive layers to the stratum corneum, the outermost layer.
Cells of the stratum corneum shed at the rate of about one cell layer per day. With aging, shedding slows and flat, dry cells accumulate, contributing to the dull appearance and rough texture of older skin.

Melanocytes in the stratum basale produce melanin, the pigment that colors the skin and helps shield it from ultraviolet ray damage. As melanin accumulates in structures called melanosomes, it darkens and obscures the mela­nosome’s internal structures. The melanosome transfers to the keratinocyte as it migrates from the stratum basale to the stratum corneum. Melanin has two major components—eumelanin, which produces a brownish black tone, and pheomelanin, which lends a yellow-red hue. The brownish color continues to migrate to the skin surface intracellularly.

In sun-damaged skin, mela­nocytes are distributed unevenly, leading to brown spots, such as freckles (ephel­ides), “liver” spots (solar lentigines), and melasma (a dark skin discoloration). In people with severe skin damage, melanin may even appear in the dermis (the deeper skin layer below the epidermis).

Besides pigmentation changes, aging skin typically has fine wrinkles and larger lines caused by facial movement. Fine lines probably stem from decreases in collagen, elastin fibers, and glycosamino­-glycans (moisture-retaining substances in the dermis) and from flattening of the rete ridges (epidermal thickenings that increase the surface area for nutrient exchange between the dermis and epidermis). Superficial peels can address these problems.

Patient preparation
Skin peels typically are done in a series of six or more sessions, with one peel administered every 1 to 2 weeks. Before the first peel, the patient must prepare the skin at home for about 2 weeks by applying a glycolic acid lotion or solution. This gently begins the exfoliation process, making the peels more evenly effective and better tolerated.

Performing a chemical peel
Glycolic peels and salicylic peels proceed through similar steps:

• The esthetician or other provider cleans the skin with a mild cleanser to remove dirt and makeup.
• She removes surface oil with alcohol or a manufacturer-recommended solution.
• She instructs the patient to close the eyes, and may provide eye protection if appropriate.
• For a glycolic acid peel, the provider may apply a pretreatment recommended by the manufacturer to augment treatment of acne, hyperpigmentation, or fine wrinkles.
• After setting a timer according to the manufacturer’s instructions, the provider applies the chemical solution to the patient’s skin, starting at the forehead and proceeding down the rest of the face to the neck. If the patient has sun damage on the chest, it should also be treated. (The neck and chest are considered parts of the face.)
• With a glycolic acid peel, the provider avoids areas of deep wrinkling, because acid accumulation can cause burns there. She monitors the skin continuously for areas of increased erythema, which signal greater acid penetration; if these appear, she must neutralize them before the peel ends.
• With a salicylic acid peel, the solution turns into a white film on the patient’s face. The provider leaves the film on the skin until the timer goes off, and then removes it with cool water.
• With a glycolic acid peel, once the timer goes off or significant erythema develops, the provider neutralizes the acid with plain water or a sodium bicarbonate solution applied with a cotton ball, a gauze pad, or a spray. She continues this process, making four passes over the entire area, until all the acid has been neutralized (as indicated by the patient nolonger feeling areas of warmth or stinging). If she fails to neutralize the acid at the right time, the peel will continue to cause epidermal destruction.
• To complete the peel, the pro­vider applies a soothing lotion. Finally, she advises the patient to use a sunblock or physical protection.

Beating the heat from a salicylic acid peel
A salicylic acid peel usually feels hotter than a glycolic peel. To help the patient through the experience, some providers use a fan or guided visualization through snow. However, the entire peel takes only about 5 minutes, so by the time the patient reports feeling hot, the sensation is likely to quickly peak and then fade.

Microdermabrasion: Chemical-free skin polishing
Instead of using chemicals to remove cells of the stratum corneum, microdermabrasion physically abrades these cells with a high-pressure flow of tiny crystals delivered by a device similar to a fine sandblaster. Using suction, the machine removes the dead cells, giving the skin a fresh, healthy-looking glow. Patients may need more than one treatment to reduce or remove fine wrinkles and unwanted pigmentation.

Various dermabrasion machines are on the market today. The older ones generate a stream of minute salt particles or aluminum oxide crystals onto the skin. The newer “diamond dermabrasion” machines avoid the gritty residue of the crystals. Instead, they use a diamond-encrusted wand to remove the skin’s top layer while a gentle vacuum sucks up the dead cells.
Here are the steps in micro­-dermabrasion:

• Using a mild cleanser, the pro­vider removes dirt, oil, and makeup from the patient’s skin.
• The patient removes contact lenses (if worn) and dons the recommended eye protection.
• The provider dons a mask.
• Holding the patient’s skin taut, the provider brushes the wand over the patient’s entire face, neck, and chest. The depth of microdermabrasion depends on the pressure and number of passes the provider makes with the wand. (Patient tolerance usually determines the number of passes; the first treatment is less aggressive than subsequent treatments.)
• The provider brushes off excess crystals from the patient’s face, and finishes by applying a soothing serum or lotion. If a newer-generation diamond-tip microdermabrasion machine is used, this step isn’t done because the machine leaves no crystals or powder on the skin.

Aftercare
To prevent further sun damage, patients should apply sunblock daily starting from the day of the first peel. Ideally, the sunblock should contain highly protective ingredients, such as zinc oxide, titanium dioxide, avobenzone (Parsol), or the recently approved ecamsule (Mexoryl). Using these ingredients during the series of peels is especially important because the thinner stratum cor­neum and superficial melanin removal achieved by the peels make the skin especially prone to sun damage, sunburn, and photosensitivity.

Several weeks after the last peel, the sun damage risk returns to what it was before the series of peels. However, patients should use sunblock daily to protect the skin.

Contraindications and precautions
Skin peels should be deferred in patients with active skin infection, collagen vascular disease, or scars less than 8 weeks old and in those who’ve received isotretinoin treatment in the past 2 to 6 months. In patients prone to herpes breakouts, peels may trigger an outbreak; before the peel, prophylactic antiviral drugs may be indicated.

Promoting the peel’s success
Skin biopsies have documented that glycolic acid peels, salicylic acid peels, and microdermabrasion effectively thin the stratum cor­neum, thicken and plump the epidermis, and increase dermal collagen production. Combining the peels with a home skin-care regimen reaps even greater benefits. Many providers advise patients to use hydroquinone, kojic acid, azelaic acid, retinoic acid, or lotions containing salicylic or glycolic acid to speed the changes and help maintain results.

But patients shouldn’t expect peels to bring permanent improvement. Just as muscles sag once a person stops working out, the effects of a skin peel fade over time if the treatments are discontinued. For most patients, a monthly peel maintains the effects achieved by a series of skin peels.

Mary Dugan, MSN, APRN-BC, is a Family Nurse Practitioner in Liberty, Mo. She and her collaborating physician, Dr. Angela Stapleton, are partners in Ageless Vision Medical Aesthetics in Liberty.