Therapeutic Update on Acne Scarring

is usually transient. While TCA cross has been demonstrated to be less effective than fractional CO2 lasers,⁷ it is certainly a reasonable option for patients (and physicians) seeking a low cost treatment with no downtime. As with any treatment, proper management of expectations is the key.

Although utilized since 1995 for many dermatologic indications, there has been a recent renewed interest in skin needling particularly as it pertains to the enhanced delivery of topical medications. Small needles attached to a rolling or stamping device penetrate 1.5 to 2mm into the dermis creating wounds in the papillary dermis that stimulate wound healing and promote tissue remodeling over several months. Skin needling is another technique that has minimal to no downtime and relatively low cost. The small wounds created can also be utilized to enhance topical drug delivery such that combining needling with chemical peels may yield improved results compared to needling alone. A 2012 study of 30 subjects randomized to receive 5 treatment of microneedling alone versus 5 treatments of microneedling plus 35% glycolic acid showed a statistically significant (P=0.001) higher rate of improvement in the glycolic acid group (62% vs 31%).⁸ Microneedling is generally considered to be safe although one case report from July of 2012 described the development hypertrophic “tram-track” scars after two treatments of needling with 2mm needles spaced 2mm apart.⁹ The case prompted authors to recommend the use of needles smaller than 2mm when treating over bony prominences such as the zygoma or temple.

Non-ablative fractional lasers create microthermal zones of injury in the lower epidermis and dermis while leaving the stratum corneum intact. Devices such as the erbium-doped glass 1550nm laser are some of the most commonly utilized in the treatment of acne scars because of their safety profile. Multiple treatment sessions are the rule, however, with the effects of the first treatment often not realized until after the second or third treatment. A total of 4 to 6 sessions are generally required to obtain the optimal result, but for those patients unable to tolerate any professional or social downtime, nonablative fractional treatments may be the best approach. A 2012 study of 87 subjects with atrophic acne scars treated for 6 sessions every 3 weeks with the Lux1540 (Palomar, Burlington, MA) reported 92% of patients with “marked” improvement defined as >50% improved from baseline.¹⁰ Confocal microscopy performed before and after treatment revealed that bright, irregularly arranged coarse collagen present before treatment was ultimately replaced by fine, net-like reticulated collagen fibers around hair follicles. Thus, it appears that the mechanism of action involves the replacement of old, defective collagen in the dermis with new, more organized collagen stimulated by the microthermal zones of injury.

For many years, the fully ablative 10,600nm CO2 was the gold standard for the treatment of acne scars. With the advent of fractional lasers, we were able to harness the power and efficacy of the CO2 laser without the extensive down time and burdensome side effects. A typical fractional CO2 protocol entails herpes simplex prophylaxis, pre-treatment with hydroquinone for skin of color patients, topical anesthesia, variable settings dependent on the device, 1-2 passes, and post-procedure occlusive ointment for up to a week.

A literature review of 20 clinical studies utilizing CO2 lasers for acne scarring published between 2008 and 2013 suggested that although all 20 studies yielded “positive” results, there were substantial limitations to the body of research overall. There was a lack of standardization across all the studies which included differences or complete lack of pre-treatment scar severity assessment, different numbers of treatments or passes per treatment, different settings and devices, and different post- treatment improvement scales.¹¹ Another important gap in the fractional CO2 literature includes lack of data on long-term outcomes.

The standard approach when using fractional CO2 for acne scarring is to perform a full-face procedure, treating the scarred areas as well as the surrounding normal skin. A 2013 study by Schweiger and colleagues sought to address whether a full face treatment is truly necessary or whether a FAST (focal acne scar treatment) technique might be equally efficacious with fewer adverse effects. In a retrospective study of 6 patients treated with fractional CO2 (Mixto Lasering Inc, Italy), they noted subjective improvement of at least 60% in all patients, and most important, there was no apparent delineation between the treated and non treated skin.¹² The authors suggest that perhaps a focally aggressive approach (14-16 Watts, Index 8, 15% coverage, 2 passes) only in the area of the scars might be equally efficacious and better tolerated than a full face treatment at more conservative settings. Notably, the protocol also includes an erbium glass fractional laser treatment one month post treatment to address any remaining PIH.

Fractional RF devices such as the E-Matrix (Syneron-Candela, CA) are quickly gaining popularity in the arena of acne scarring because of the relative ease of performing the procedure and the favorable safety profile particularly for skin of color patients. Unlike lasers, RF devices utilize thermal energy to create deep dermal heating without a target chromophore and thus are said to be “color-blind.” A 2013 split-face study of 20 Thai patients compared the efficacy of 3 monthly treatments with the E-Matrix fractional RF to the non-ablative Fraxel re: store (Solta, CA) for the treatment of atrophic acne scars¹³. Both devices resulted in statistically significant improvement