Ethyl Chloride as an Antipruritic Agent: A Double-Blind Placebo-Controlled Prospective Study

Abstract

Background: Ethyl chloride (EC) is usually used as a topical anesthetic spray agent. However, its antipruritic effects have never been studied, to the best of our knowledge. Methods: A double-blind placebo-controlled prospective study. Overall, 51 healthy volunteers underwent a histamine skin prick test on both arms in order to trigger local pruritus. Thereafter, the affected areas were treated with an EC spray on one arm and a saline spray (placebo) on the other. Subjects as well as researchers were blind to which sprays were used. Subjects reported improvement in pruritus following EC/placebo and rated the intensity of pruritus by using a validated questionnaire and a visual analog scale. The flare and wheal reactions were measured in both arms before and following treatment with EC/placebo. Results: Significant improvement in pruritus was reported more frequently following treatment with EC compared with placebo (84 vs. 16%; p < 0.0001). Significant reduction in pruritus intensity was reported immediately and 15 min following treatment with EC compared with placebo (p < 0.05). There was no significant difference between EC and placebo in terms of the flare and wheal reactions. Conclusions: EC is an effective antipruritic agent, and it does not change the wheal and flare reactions, making it ideal for treating pruritus secondary to allergy skin tests without masking their results.