BACKGROUND Intranasal antihistamine has not been thoroughly studied in the treatment of rhinitis of different etiologies. This study was designed to show the comparative efficacy of nasal antihistamine and nasal corticosteroid in patients with allergic rhinitis (AR) and nonallergic rhinitis (NAR). METHODS A comparison of the efficacy of azelastine nasal spray (AZENS) versus triamcinolone acetonide nasal spray (TANS) on total nasal symptom scores (TNSS), nasal peak inspiratory flow rate (nPIFR), and nasal cytology was studied in a 2-week randomized parallel-group trial. The Epworth Sleepiness Scale (ESS) and health-related quality of life (HRQoL) were also analyzed. RESULTS The study group consisted of 132 patients (100 women and 32 men) with a mean age of 33.14 +/- 12.52 years. Sixty-nine patients had AR and 63 had NAR. Although TNSS including sneezing, itching, rhinorrhea, congestion-but not anosmia-significantly improved in both groups, intranasal azelastine reduced ocular symptoms greatly compared with intranasal triamcinolone (p = 0.05). Patients with NAR seemed to respond more to TANS, whereas AZENS was more useful in AR. The nPIFR improved in AR and NAR, with no significant difference between the treatment groups. Neither intranasal azelastine nor intranasal triamcinolone changed cytology in nasal lavage. Both medications were well tolerated, but AZENS led to more adverse events than TANS (56.9 and 19%, respectively; p = 0.001), mainly because of bitter taste. Scores on each domain of generic HRQoL (36-Item Short-Form Health Survey) and mini-rhinitis QoL questionnaires, as well as ESS score, significantly improved in both groups, irrespective of rhinitis etiology. CONCLUSIONS In this first comparative demonstration, AZENS appears to be as effective as triamcinolone in symptom scores, nPIFR, ESS, and HRQoL, equally in AR and NAR.