Acne scars are potentially socially debilitating lifelong reminders of the condition. Fortunately, modern laser therapy allows dermatologists to offer their patients hope for improvement. Prior to initiating laser therapy for acne scars it is important to consider the types of scars encountered. Laser is not a “one-size fits all” treatment — erythematous/hyperpigmented macular, hypertrophic, atrophic, ice pick, rolling or boxcar scars can each necessitate unique interventions.
Pulsed light approach
Pink-erythematous scars result from dilatation of dermal blood vessels. A tincture of time can be sufficient for some red scars to resolve, but to offer patients expeditious improvement a variety of devices are available, including intense pulsed light, pulsed dye laser (PDL, 585 nm–595 nm; Alster TS, McMeekin TO. J Am Acad Dermatol. 1996;35(1):79-87) and the potassium titanyl phosphate laser (KTP, 532 nm).
These long-pulsed devices take advantage of oxyhemoglobin’s avid absorption of light in the shorter wavelength visible spectrum to selectively target the dilated blood vessels while minimizing collateral heat spread. Treatments are safe in hair-bearing areas, though we recommend a close shave for men prior to treatment.
With the aforementioned devices the authors prefer using the shorter end of the available pulse durations. A South Korean group reported excellent results with both the PDL and the 1064 nm neodymium-yttrium-aluminum-garnet (Nd:YAG) for atrophic acne scars (Lee DH, Choi YS, Min SU, et al. J Am Acad Dermatol. 2009;60(5):801-807).
This split-face trial of 18 patients receiving four sessions with each laser revealed clinical scar improvement as well as histologic evidence of neocollagenesis. Hyperpigmented scars may be approached with the same devices (IPL, KTP or PDL) though quality-switched lasers (KTP, 694 nm ruby, 755 nm alexandrite, and Nd:YAG) with pulse durations in the nanosecond domain offer another option.