Efficacy and Side Effects of Fractional Carbon Dioxide Laser for Acne Scars, Keloids, and Striae Albae in the Dermatovenereology Clinic of Tertiary Hospital: A Retrospective Study Riezky Januar Pramitha 1 , Iskandar Zulkarnain 1 , Evy Ervianti 1 , Rahmadewi 1 , Afif Nurul Hidayati 1 , Budiono 2 , Diah Mira Indramaya 1 , Trisniartami Setyaningrum 1 , Irmadita Citrashanty 1 , Maylita Sari 1 , Menul Ayu Umborowati 1 , Bagus Haryo Kusumaputra 1 , Muhammad Yulianto Listiawan 1 1 Department of Dermatology and Venereology, Faculty of Medicine, Universitas Airlangga, Dr. Soetomo General Academic Teaching Hospital, Surabaya, Indonesia 2 Department of Public Health Sciences, Faculty of Medicine, Universitas Airlangga, Surabaya, Indonesia ABSTRACT Background: Fractional Carbon Dioxide (CO2) LASER has better efficacy compared to conventional LASER in treating scar tissue such as acne scars, keloids, and striae albae. However, a population with darker skin has a higher risk of side effects, especially in post-inflammatory hyperpigmentation. Purpose: To evaluate the efficacy and side effects of fractional CO2 LASER in new patients with acne scars, keloids, and striae albae in the Dermatovenereology outpatient clinic. Methods: Retrospective analysis was done on 42 medical records of patients who met the inclusion criterion, which was those who have undergone fractional CO2 LASER treatments. The efficacy and side effects of the therapy were identified and analyzed using the Statistical Package for Social Sciences (SPSS) version 17 program. Result: A total of 42.9% of patients underwent fractional CO2 LASER treatments for acne scars, while 31% and 26.1% of patients received treatments for keloids and striae albae, respectively. There was a statistically significant decrease in the degree of acne scar (2.72 ± 0.83), keloid height (2.2 ± 0.405), and striae width (0.39 ± 0.02). The statistically significant side effects were hyperpigmentation (59.5%), crustae (26.2%), erythema ≥ for 4 days (19%), and new acne (19%). Conclusion: Fractional CO2 LASER was effective for treating scar tissue (acne scars, keloids, and striae albae) with a higher incidence of side effects in population with darker skin and post-inflammatory hyperpigmentation. Keywords: Fractional CO2 LASER, side effects, efficacy, scar. Correspondence: Muhammad Yulianto Listiawan, Department of Dermatology and Venerology, Faculty of Medicine, Universitas Airlangga, Dr. Soetomo General Academic Hospital, Surabaya, Jl. Mayjen Prof. Dr. Moestopo No. 6-8 Surabaya 60131, Indonesia. Phone: (031) 5501609, e-mail: yuliantowawan@yahoo.com BACKGROUND Light Amplification of Stimulated Emission of Radiation (LASER) is a device that produces electromagnetic rays with monochromatic, coherent, and collimated characteristics. The emergence of the Fractional Photothermolysis (FP) theory, which was developed to overcome the side effects of conventional LASER, became a milestone in the development of LASER in the field of dermatology. FP is divided into ablative (aFP) and non-ablative Fractional Photothermolysis (nFP). One of the rapidly developed and frequently used aFP modalities is the fractional CO2 LASER. Fractional CO2 LASER is not only effective for skin rejuvenation but also for treating scar tissue, such as acne scars, keloids, and striae albae (SA). 1-4 Research conducted by Chapas and colleagues on acne scar in patients with skin types I to III stated that there was an increase of 25% - 50% in texture, atrophy, and improvement of the acne scar after receiving treatment with fractional CO2 LASER. 6,7 A study by Scrimali and colleagues in 2010 stated that there was a decrease in the size of keloid height by 20–25% in 6 months post-therapy, while a study on SA by Naeni in 2014 stated that there was a decrease in SA measurements with the average of 0.62 ± 0.53 in length and 0.41 ± 0.43 in width. Although it has better efficacy compared to conventional LASER, fractional CO2 LASER has a higher risk of side effects such as hyperpigmentation, erythema, edema, crustae, squama, or bacterial or viral infections, especially in darker skin phototypes such as the Asian population. 8-10 This is the authors’ background to discuss the efficacy and side effects of using fractional CO2 LASER in new patients with acne scars, keloids, and SA. 19