Background: Perennial rhinitis is a common disease that has many similarities with bronchial asthma. Early treatment with inhaled steroids has improved asthma symptoms, lung function, and bronchial hyperreactivity, but it has not been studied in perennial rhinitis. Objective: The main objective was to determine whether early introduction of long-term daily intranasal steroid treatment would have a positive effect on the clinical course and outcome of perennial rhinitis compared with the effect of an antihistamine. A secondary objective was to compare the clinical efficacy of intranasal budesonide and oral cetirizine. Methods: One hundred forty-three adult patients with newly detected perennial allergic or nonallergic eosinophilic rhinitis of 1 to 3 years’ duration were randomized to receive budesonide dry powder, 400 μg (delivered dose of 280 μg) intranasally, or cetirizine, 10 mg orally, once daily for 1 year. At the end of the double-blind treatment period, medication was stopped, and the patients were followed for another year, during which time they could use 14-day courses of intranasal budesonide as needed to control rhinitis relapses. The main outcome measures were the time to first relapse and the number of relapses during the second year. Nasal symptom scores, nasal smear eosinophilia, and nasal peak expiratory flow were used to compare the clinical efficacy of the 2 treatments. Results: During the randomized phase of the study, budesonide was significantly more effective than cetirizine in relieving nasal symptoms. Nasal peak expiratory flow improved significantly in budesonide-treated patients compared with in patients receiving cetirizine. After discontinuation of randomized treatment, 38% of budesonide-treated and 56% of cetirizine-treated patients had a relapse within the first month (P = .04). The median time to first relapse was longer in budesonide-treated patients than in cetirizine-treated patients (62 vs 20 days), although the difference was not significant. Fourteen-day courses of budesonide provided effective control of relapses; the mean number of relapses was 4.0 versus 5.4 in the groups previously treated with budesonide or cetirizine, respectively. Both treatments were well tolerated throughout the study. Conclusions: Budesonide is significantly more effective than cetirizine in controlling perennial rhinitis. After stopping treatment, budesonide better prevents relapses for 1 to 2 months compared with cetirizine. Periodic therapy with budesonide may be sufficient to control symptoms in most patients who have relapses. (J Allergy Clin Immunol 2002;109:426-32.)