Nelson Lee Novick, M.D. is a Clinical Professor of Dermatology at Mount Sinai School of Medicine in New York City, an Attending Physician, and a former OPD Clinic Chief within the department of dermatology of the Medical Center. He is board-certified both in internal medicine and dermatology and is a Fellow of the American... more
In my daily practice devoted to treating all kinds of scars, most especially those arising from acne, I'm sorry to say that I routinely consult with patients who have not only suffered from years of acne but subsequently years of fruitless, disappointing attempts to treat the resultant acne scars. With a host of supposedly "next big thing" Fraxel lasers or radiofrequency, as well as other "bells and whistles" devices whose science to support their use often lags far beyond any hard data to advocate for them. For years I have been writing Q&As and articles in which I have cautioned readers against falling prey to the intense marketing hype that surrounds the use of so many of the "bells and whistles" devices currently out there. Instead, I have urged readers to vet the relatively inexpensive and safe techniques that have truly proven effective and have stood the test of time. Any treatments or combination of techniques for acne scars must be tailored to the specific locations, as well as the number, kind, depth, diameter, and distensibility of the scars.
To appreciate how best to treat acne scars, you first need to understand the various kinds of acne scars that may result from episodes of prolonged, uncontrolled acne breakouts over the years. In general, there are two broad categories: indented (depressed, atrophic, sunken) scars and elevated scars (hypertrophic, keloid, and papular acne scars). The principles of treatment are actually quite simple and straightforward. Depressed scars, i.e. those whose bases are sunken below the level of the surrounding skin surface, need to be elevated and smoothed, and those that are elevated above the skin surface must be flattened. As depressed scars are far and away more common than elevated ones, I have decided to devote this blog post to their treatment.
Boxcar scars, rolling scars, and ice pick scars are the three common types of depressed acne scars. Boxcar scars, as the name implies have square, almost vertical walls surrounding a deep base, much like the Palisades rise vertically and tower over the Hudson River. Rolling scars, on the other hand, may be shallow or deep, but have walls that more gently slope upwards and outwards at about a 30-45 degree angle above the base below. Depressed scars, particularly the boxcar variety, are typically tethered tightly down by bands of thick, fibrous scar tissue. Not uncommonly, when acne has been particularly troublesome and ongoing, there can be so much general damage and thinning of the skin on a microscopic level (not necessarily easily visible to the naked eye).
This occurs within the cheeks and temples, that these whole areas or fields may sink in to such a degree as to worsen the appearances of any individual overlying boxcar and rolling scars that lay scattered over what can be likened to a large sinkhole. This kind of generalized tissue sinking of whole areas, in the cheeks, temples, or jawline, can be more appropriately be referred to as "field atrophy." Last but not least, there are ice pick scars, named because of their resemblance to the holes that would be left in ice by a narrow pick chipping away at it; they are in fact be the most common type of depressed acne scar encountered. By definition, ice pick scars tend are quite deep and narrow v-shaped pits that frequently resemble, and are often confused with enlarged, dilated pores.
Unless there are very few scars, it is uncommon for persons to have only one type. Usually, a mix of rolling, boxcar, and ice pick scars is found, each scar requiring its own treatment approach. Subcision is a technique whereby an appropriately sized needle, cannula, or trochar is inserted below the skin surface of the scar, under local anesthesia, and used to break up and release the fibrous tethers. A small pocket of blood then accumulates under each scar, which supplies the necessary growth factors and wound healing factors that stimulate new, native collagen and elastic fiber production that ultimately leads to elevation and smoothing of the scar. When a larger area, such as a cheek or temple is atrophic, a "field subcision" can be used to reinflate and smooth the area.
The difference between a field subcision and an individual subcision is simply the size of the area treated. Following a field subcision, smaller subcisions may be used to elevate and smooth individual boxcar and rolling scars. Subcisions may be performed either alone or in combination with fillers, although I would not recommend permanent fillers, such as Bellafill, as these may sometimes give rise to difficult-to-treat bumps and lumps complications five, ten or even twenty years after their use - a reaction that may occur in areas upset by manipulation, such as during dental or plastic surgical procedures. A treatment series of four to six subcision sessions spaced at six-week intervals are usually required in order to achieve a sixty to eighty percent overall improvement in scar appearance.
TCA CROSS, a technique that utilizes very potent concentrations (80%-100%) of trichloroacetic acid, is a preferred method for dealing with ice pick scars, dilated pores, and very narrow-based boxcar scars. Here the acid is carefully inserted with a fine wooden applicator or needle down the narrow shaft of each scar or pore with the intent of irritating the lining of the scar or pore. This in turn leads to new collagen and elastic fiber production, with the resulting narrowing of the scar. It is important to once again note that, as with subcision, one can realistically expect between a 50%-80% overall improvement in appearance following a series of three to six treatment sessions. Finally, when additional improvement in superficial surface texture and color is still desired, professional medical microneedling, which employs an array of very fine stainless steel needles to penetrate the scars ( performed either manually with dermal rollers or electrically in the form of pens) may then be used as "finishing touch."