Laser treatment of specific scar characteristics in hypertrophic scars and keloid: A systematic review

Background: Hypertrophic scarring and keloid can cause significant emotional and physical discomfort. Cosmetic appearance, functional limitations, pain and pruritus form a degree of impairment. While the etiology is not fully known, there is a wide array of treatment options, which include excision, radiation, cryotherapy, silicone gel sheeting, and intralesional injections. A relatively new modality is laser therapy. While results are promising, the number of different laser systems is substantial. This review evaluates the available evidence regarding outcomes on specific objective characteristics (i.e., erythema, pigmentation, height, and pliability) of the different laser systems. Methods: A systematic literature review was performed using MEDLINE, Cochrane Library, and EMBASE. Data on scar characteristics were extracted from scar scales Vancouver Scar Scale (VSS) and Patient and Observer Scar Assessment Scale (POSAS), and from objective measurement tools. Results: Heterogeneity was seen in a lot of aspects: maturity of scar, origin of scar, follow-up, and number of treatments. The fractional ablative lasers CO2 10,600 nm and Er:YAG 2940 nm were found to produce the best results regarding erythema, height, and pliability, while the flash lamp-pumped pulsed dye laser (PDL) 585 nm scored slightly below that. Conclusions: Laser systems, and specifically the fractional ablative lasers CO2 and Er:YAG, improved various characteristics of excessive scarring. An overview of preferred laser modality per scar characteristic is presented. Accounting for the methodological quality and the level of evidence of the data, future research in the form of randomized trials with comparable standardized scar scales is needed to confirm these results.