BACKGROUND: Asthma and rhinitis often co-occur, and this potentially increases the disease severity and impacts negatively on the quality of life. We studied disease severity, airway responsiveness, atopy, quality of life and treatment in subjects with both asthma and rhinitis compared to patients with asthma or rhinitis alone.

METHODS: We examined 878 patients: 182 with asthma, 362 with rhinitis and 334 with both asthma and rhinitis. All had a clinical interview concerning severity of symptoms, treatment, and quality of life, a skin prick test, a lung function test and a bronchial provocation with methacholine.

RESULTS: Patients with both asthma and rhinitis had less severe asthma based on the frequency of respiratory symptoms compared to patients with asthma alone (55%vs 66%P = 0.01). On the contrary, they were more airway responsive (P < 0.05) and had more perennial allergy (P < 0.001). Asthmatics had poor perception of the general health, independent of rhinitis (P < 0.001). No differences were found in asthma-specific quality of life, whereas rhinitis-specific quality of life was worse in those with both asthma and rhinitis compared to those with rhinitis alone (P < 0.01). Subjects with both diseases were undertreated in 85% of the cases.

CONCLUSION: We encourage that these observations be used in the evaluation and treatment of patients with asthma and rhinitis and that they contribute to the understanding of asthma and rhinitis as a uniform airways disease.