Clinical Factors Affecting the Effectiveness of 1550-nm Erbium-Doped Fractional Photothermolysis Laser for Individual Atrophic Acne Scar Types

INTRODUCTION: Although non-ablative fractional resurfacing is frequently used for atrophic acne scars, few studies have examined clinical factors affecting the effectiveness of non-ablative fractional laser in individual atrophic acne scar types (icepick, rolling, and boxcar scars). Herein, we evaluated the clinical factors affecting the effect of non-ablative fractional laser for individual atrophic acne scar types using objective assessment tools. METHODS: Thirty-one patients who had been treated by 1550-nm erbium-doped fractional laser for atrophic acne scars were retrospectively reviewed. Icepick, rolling, and boxcar scars were counted using photographs, and acne scar reduction efficiency (ASRE%; the percentage reduction of post-acne scar count from baseline counts) was calculated. RESULTS: The median count of each scar type was significantly reduced at the end of the final session. Boxcar scars responded better (median ASRE 59.2%) than rolling (ASRE 40.6%, p = 0.017) and icepick scars (ASRE 19.1%, p = 0.010). Concomitant isotretinoin use resulted in a greater ASRE and a significantly greater improvement in icepick scars. Patients aged 25 years or younger showed a higher ASRE, with a greater improvement in boxcar scars. CONCLUSION: 1550-nm fractional laser treatment for atrophic acne scars was more effective in patients who were younger and taking isotretinoin concurrently.