Effect of the topical anesthetic EMLA on the efficacy of pulsed dye laser treatment of port-wine stains. EMLA cream (Eutectic Mixture of Local Anesthetics) is a new topical anesthetic composed of 25 mg lidocaine and 25 mg prilocaine in an oil-in-water emulsion cream. It has been found to be very effective for local anesthesia prior to venepuncture, minor surgical procedures, and pulsed dye laser (PDL) therapy for port-wine stains (PWS) in children. However, since EMLA may cause vasoconstriction of cutaneous vessels, we tried to determine whether pretreatment with EMLA decreases the efficacy of subsequent PDL treatment. We report eight patients between the ages of 4 and 32 years with PWS who received two test site treatments prior to PDL treatment. One site was pretreated with EMLA cream under occlusion for 60 minutes and then left unoccluded for 15 minutes prior to PDL test treatment. The other site, in the same area of the PWS and patient's body, was not pretreated with EMLA. The test sites were compared 6-8 weeks later to determine whether EMLA decreased the degree of lightening of the PWS compared to the non-EMLA-treated site. We conclude that EMLA is an effective topical anesthetic for PDL treatment of PWS and does not adversely affect the efficacy of the treatment. 