Suppression of the early and late cutaneous allergic responses using fexofenadine and montelukast

Background: The relative contribution of histamine and the cysteinyl leukot rienes to the early and late cutaneous allergic responses (ECAR and LCAR) c an be studied using antagonists of these mediators. Objective: To determine the relative suppression of the ECARs and LCARs usi ng standard doses of an H-1-receptor antagonist, a cysteinyl leukotriene(1) -receptor antagonist, and the two antagonists administered concurrently. Methods: We carried out a prospective, randomized, double-blind, placebo-co ntrolled, four-way crossover study in 12 highly allergic participants. Intr adermal tests with standardized allergen, and with histamine phosphate, LTD 4, and saline controls were performed on 5 different test days as follows: pretreatment baseline and at steady state immediately after the seventh and last dose of a 1-week course of treatment with once-daily fexofenadine, 12 0 mg; montelukast, 10 mg; fexofenadine and montelukast administered concurr ently; or placebo. On each test day, the skin test results were read at int ervals from 0.25 to 24 hours after the intradermal injections were performe d. Results: After allergen injection, compared with baseline, all treatment re gimens significantly decreased the ECAR and LCAR. After allergen injection, compared with placebo, fexofenadine significantly decreased the ECAR and t he LCAR from 0.25 to 2 hours and at 8 hours. Montelukast did not significan tly decrease the ECAR or LCAR. Fexofenadine and montelukast administered co ncurrently were not more effective than fexofenadine alone at any time. In the control skin tests, compared with placebo, fexofenadine, but not montel ukast, significantly decreased the histamine-induced response, and monteluk ast, but not fexofenadine, significantly decreased the LTD4-induced respons e. Conclusions: Fexofenadine and montelukast administered concurrently were no t significantly more effective than fexofenadine alone in decreasing the EC AR and LCAR. Montelukast does not need to be discontinued before allergen s kin testing. Further studies of the effect of concurrent treatment with hig her doses of a histamine antagonist and a leukotriene modifier on the aller gic response in the skin are needed.