Relief of experimentally induced pruritus with a novel eutectic mixture of local anaesthetic agents

Abstract
The effectiveness of a eutectic mixture of the local anaesthetics lignocaine and prilocaine (EMLA® cream) in relieving artificially induced pruritus was examined in 20 volunteers. The study was conducted in two parts. In part one, the effect of EMLA on the threshold concentration of histamine necessary to induce pruritus was assessed by a double‐blind placebo controlled method. In part two, the effect of EMLA on the perception of pruritus induced by the artificial pruritogens cowhage and papain was assessed by a single blind method. Some subjects were less sensitive to histamine after placebo cream treatment, but all subjects showed a marked reduction in sensitivity to histamine after EMLA treatment. The difference between EMLA and the placebo treatment was statistically significant. The EMLA preparation was found to be effective in alleviating pruritus induced by cowhage and papain and this effect was also statistically significant. Thus, EMLA cream was found to be effective in reducing experimentally induced pruritus and, therefore, may be useful in some clinical circumstances where persistent itch is a distressing symptom.