摘要： Pulsed-dye laser (PDL) is the treatment of choice for port wine stain (PWS), and the development of purpura is considered a therapeutic endpoint. Changes in PWS vasculature observed by dermoscopy immediately after laser irradiation have been suggested to predict the minimal effective fluence. The current study aimed at comparing these changes with purpura as a therapeutic endpoint. Fifty-six PWS patients, randomized into two groups, received five monthly PDL sessions (595 nm and 10 mm spot size). At the first visit, patients received multiple gradually increasing test irradiations. Patients in the first group were treated with the lowest dose that resulted in 24-hr-lasting purpura, while patients in the second group were treated with the lowest dose that resulted in vessel disappearance observed by dermoscope. No statistically significant differences were observed between the two groups (the dermoscopic and the purpuric) regarding mean average improvement (42.4 and 37.32%, respectively, p = .32), grade of improvement (p = .44), and the rate of side effects (0 and 13.79%, respectively, p = .13). In conclusion, the immediate post-irradiation vessel disappearance (detected by dermoscope) is comparable, in safety and efficacy, to purpura as a therapeutic endpoint and maybe more time-saving and more accepted cosmetically.