Ethyl chloride as an antipruritic agent: a double-blind placebo-controlled prospective study.

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.