PREVENTION OF POISON-IVY AND POISON OAK ALLERGIC CONTACT-DERMATITIS BY QUATERNIUM-18 BENTONITE

Background: Poison ivy and poison oak are the most common causes of al lergic contact dermatitis in North America. Objective: We investigated whether a new topical lotion containing 5% quatemium-18 bentonite pre vents experimentally induced poison ivy and poison oak allergic contac t dermatitis. Methods: A single-blind, paired comparison, randomized, multicenter investigation was used to evaluate the effectiveness and s afety of quaternium-18 bentonite lotion in preventing experimentally i nduced poison ivy and poison oak allergic contact dermatitis in suscep tible volunteers. One hour before both forearms were patch tested with urushiol, the allergenic wsin from poison ivy and poison oak, 5% quat emium-18 bentonite lotion was applied on one forearm. The test patches were removed after 4 hours and the sites interpreted for reaction 2, 5, and 8 days later. The difference in reactions between treated and u ntreated patch test sites was statistically analyzed. Results: Two hun dred eleven subjects with a history of allergic contact dermatitis to poison ivy and poison oak were studied. One hundred forty-four subject s had positive reactions to urushiol. The test sites pretreated with q uaternium-18 bentonite lotion had absent or significantly reduced reac tions to the urushiol compared with untreated control sites (p < 0.000 1) on all test days. When it occurred, the reaction consistently appea red later on treated than on control sites (p < 0.0001). One occurrenc e of mild, transient erythema at the application site was the only sid e effect from the quatemium-18 bentonite lotion.Conclusion: Quaternium -18 bentonite lotion was effective in preventing or diminishing experi mentally produced poison ivy and poison oak allergic contact dermatiti s.