Desloratadine, a potent, once-daily, orally active, nonsedating, histamine H1-receptor antagonist, inhibits the release of histamine and other inflammatory mediators. Once-daily desloratadine therapy rapidly reduces the symptoms of perennial allergic rhinitis and seasonal allergic rhinitis (SAR), reduces the use of inhaled albuterol by patients with SAR and concomitant asthma, and improves symptoms and quality of life in patients with chronic idiopathic urticaria. An open-label, observational study in SAR patients revealed that desloratadine therapy significantly reduced nasal, ocular, dermal, asthma, and total symptoms, and enabled half of the patients with concomitant asthma to reduce their use of asthma medications. Globally, more than 91% of patients and physicians judged desloratadine to have excellent or good efficacy, and more than 98% judged it to have excellent or good tolerability. Furthermore, desloratadine therapy improved quality of life, decreasing by more than 10-fold the percentage of patients whose daily activities and/or sleep were moderately or severely affected by SAR. Allergic rhinitis, a major chronic airway disease that is a risk factor for asthma, warrants extended diagnostic procedures and well-tolerated therapy that encompasses the entire airway, addresses multiple steps in the allergic inflammatory cascade, and is effective on nasal, ocular, dermal, asthma, and total symptoms.