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Editor’s note: This article has been excerpted from the new Physiology of the Skin, Third Edition book by Zoe Draelos, MD, and Peter T. Pugliese, MD, which was released in February 2011 by Allured Books. The book can be purchased online at www.AlluredBooks.com.
There are two basic methods of altering the surface of the skin: chemical and physical. Chemical alterations are accomplished by applying acids to the skin causing the cells of the stratum corneum to separate and slough off. Superficial chemical peels using glycolic and salicylic acid make the skin smooth and soft by this mechanism. Another mechanism of removing the stratum corneum cells is to physically rub, blast or grind them off. This physical type of removal is used in microdermabrasion and dermabrasion.
Dermabrasion was first developed as a medical procedure to improve the appearance of scarred skin and was later adapted to photoaged skin. It was originally done with a wire brush that literally ground off the surface of the skin. This procedure was quite bloody and painful, but was successful in improving severely scarred skin by smoothing the surface of the skin. The healing time was prolonged, taking weeks for the scabs to resolve and months for the redness to improve. In addition, sometimes the treated skin became lighter than the untreated skin as it healed, making skin color an issue. Dermabrasion could not be used on people who had deeply pigmented skin.
This rather aggressive dermatologic procedure has been refined through the introduction of new equipment. Modern dermabrasion equipment resembles a hand-held rotary motor drill with a small diamond-coated bit that is used to grind off the skin. The small diamond pieces are sharp, but can be easily controlled as the bit is moved over the surface of the skin. Dermabrasion was the standard treatment for deep wrinkles of the face from severe photodamage until the carbon dioxide (CO2) laser was adapted for dermatologic use. For a time, dermabrasion was rarely done, but it is making a resurgence, especially for wrinkles on the upper lip that do not respond to many other modalities.
The concept of dermabrasion was adapted for use by skin care professionals with the invention of the microdermabrasion machine. The microdermabrasion machine removed the top layer of stratum corneum physically, but did not enter the living part of the skin like medically administered dermabrasion did. This made the procedure safe to use without the possibility of bleeding or scarring.
Microdermabrasion operates on the premise that encouraging exfoliation of the skin is desirable. The word “micro” is used to separate this procedure from true dermabrasion, where the deeper layers of the skin are removed. By using a motorized brush system or bombarding the skin with high-speed particles, it is possible to remove desquamating corneocytes, and make the skin smoother and softer with a better color. It is important not to go any deeper into the skin than the first few layers of stratum corneum to avoid scarring and other problems. Microdermabrasion can be used by trained skin care professionals because it does not enter the living layers of the skin; any procedure that enters the living layers of the skin and causes bleeding should be performed by a physician.
Microdermabrasion improves the appearance of several aspects of the skin, such as increased pigment, which may be contained in the outer corneocytes. This pigment may make the skin look freckled due to the presence of lentigenes, the medical term for brown spots, and scaling brown growths, known as seborrheic keratoses. Microdermabrasion can remove the skin scale that contains the pigment, making the skin more evenly colored. However, it is possible for the lentigenes and seborrheic keratoses to reappear as the skin cells again produce irregular pigment, making the improvement temporary.
There is some evidence that repeated microdermabrasion can have a longer-lasting impact on the amount of ground substance in the skin responsible for holding water. The minor skin injury induced by microdermabrasion may cause wounding that encourages the skin to heal. This healing can stimulate the replacement of skin structure and improve the appearance of photoaged skin. Controlled wounding is the reason both dermabrasion and laser resurfacing improve skin appearance. This same effect is seen to a much lesser degree with microdermabrasion, especially if the procedure is repeated every two to four weeks.