“…187,189,190 The erbium:YAG laser, developed to reduce the morbidity associated with CO 2 laser resurfacing, 187 has demonstrated comparable results with fewer side effects in some studies. 148 The biochemical changes seen after CO 2 laser resurfacing include increased mRNA of several cytokines (IL-1b, TNF-a, and TGF-b1), type I and type III procollagen, and MMPs. 191 Undesired effects of ablative systems include hypertrophic scar formation and pigmentary alterations.…”