title: Treatment of punched-out atrophic and rolling acne scars in skin phototypes III, IV, and V with variable square pulse erbium:yttrium-aluminum-garnet laser resurfacing.
abstract: BACKGROUND
  Treatment of acne scars remains a challenge, especially in dark-skinned individuals. Treatment parameters may be optimized by selecting appropriate pulse width and laser energy that enhance tissue thermal response with limited morbidity.
  
  
  OBJECTIVE
  To determine the efficacy and side effects of variable square pulse (VSP) erbium:yttrium-aluminum-garnet (Er:YAG) laser resurfacing for treatment of punched-out atrophic and rolling acne scars. METHODS Twenty-four subjects with acne scars were treated monthly for 2 months with four passes of VSP Er:YAG laser resurfacing using a 7-mm spot size and a fluence of 0.4 J/cm(2). Subjects were divided into two groups and treated with two different pulse widths: 300 micros (short pulse, SP) and 1,500 micros (extra-long pulse, XLP). Objective and subjective assessments were obtained at baseline and 1, 2, and 4 months after treatment.
  
  
  RESULTS
  In the SP group, skin smoothness improved significantly (p<.01); in the XLP group, skin smoothness (p<.05) and scar volume (p<.05) improved significantly from baseline. Adverse effects consisted of transient postinflammatory hyperpigmentation (18%) and acneiform eruption (9%).
  
  
  CONCLUSIONS
  Low-fluence VSP Er:YAG laser resurfacing is a promising treatment option for acne scars, with minimal risk of side effects. Laser pulse width and energy determine the efficacy and the risk of side effects. The authors have indicated no significant interests with commercial supporters.
authors: Department of Dermatology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand.
authors: Rungsima
authors: R
authors: Wanitphakdeedecha
authors: Woraphong
authors: W
authors: Manuskiatti
authors: Sujittra
authors: S
authors: Siriphukpong
authors: T Minsue
authors: TM
authors: Chen
mesh_terms: D000152:Acne Vulgaris / Q000150:complications* / Q000473:pathology / Q000532:radiotherapy; D000293:Adolescent; D000328:Adult; D002921:Cicatrix / Q000209:etiology / Q000473:pathology / Q000532:radiotherapy*; D005500:Follow-Up Studies; D006801:Humans; D007834:Lasers; D053844:Lasers, Solid-State / Q000627:therapeutic use*; D028022:Low-Level Light Therapy / Q000295:instrumentation*; D008297:Male; D008875:Middle Aged; D017060:Patient Satisfaction; D012880:Skin Pigmentation; D016896:Treatment Outcome; D055815:Young Adult