The purpose of this study is to determine the effect of cetirizine, an oral antihistamine, on
wheezing in patients with allergic rhinitis. Patients presenting to the pediatric emergency
department who have a history of allergic rhinitis and who are wheezing will be asked to
participate. Half of patients will receive a dose of cetirizine and the other half will
receive placebo and their response will be monitored over the course of their emergency
department visit with vital signs, physical examinations, and measurement of
bronchoconstriction with spirometry.