Low‐fluence 585 nm Q‐switched Nd:YAG laser: A novel laser treatment for post‐acne erythema

Background Persistent post‐acne erythema is one of the most common aesthetic sequelae to arise after active acne resolves. The treatment remains challenging due to lack of effective laser modalities. Objectives To evaluate the safety and efficacy of a low‐fluence 585 nm Q‐switched Nd:YAG laser for the treatment of post‐acne erythema. Materials & Methods Twenty‐five patients with post‐acne erythema were treated with a low‐fluence Q‐switched Nd:YAG laser using the 585 nm Gold Toning™ handpiece (5 mm spot size, 5–10 ns, 0.30–0.55 J/cm 2 , 2–4 passes) for three sessions at 2‐week intervals. Erythema lesion (macules) count, inflammatory acne (papules, pustules) count, erythema index, degree of post‐acne erythema and overall improvement in post‐acne erythema and acne scar were assessed at baseline, every 2 weeks and 6 weeks after the last treatment. Subjective degrees of satisfaction were also evaluated. Adverse events were recorded and pain was scored using a visual analog scale (VAS). Results At 6 weeks after 3 sessions of laser treatment, all patients demonstrated clinical improvement. Erythema lesion counts decreased by 20.1% (versus baseline) after the first treatment ( P = 0.004), by 32.7% after the second treatment, by 46.5% at 2 weeks after the third treatment and by 58.7% at the 6‐week follow‐up (all P < 0.001). Significant improvements were also noted in erythema indices (22.29 ± 2.4 to 17.51 ± 1.8) and mean post‐acne erythema scores after the first treatment (both P < 0.001). The mean scores of independent physician assessments were 4.04 ± 0.9 in term of the improvement of post‐acne erythema and 3.44 ± 0.9 in the improvement of scaring. In addition, we could observe a significant decrease in inflammatory acne lesion counts after two laser treatments with a decrease in mean lesion counts by 67% at the 6‐week follow‐up. Treatment was well‐tolerated and adverse effects were limited to transient erythema and edema at treatment sites. Conclusions Low‐fluence 585 nm Q‐switched Nd:YAG laser treatment is safe and effective for the treatment of post‐acne erythema with minimal discomfort and quantifiable improvement in the appearance of early acne scarring and inflammatory acne. Lasers Surg. Med. 47:148–155, 2015. © 2015 Wiley Periodicals, Inc.