Association between allergic rhinitis and asthma in a Northern Alberta cohort

BACKGROUND Many published epidemiologic studies confirm a marked increase in the prevalence of asthma and allergic rhinitis. The link between allergic rhinitis and asthma has been extensively studied and approximately 75% of patients with asthma have allergic rhinitis. The proportion of patients with asthma in populations of allergic rhinitis patients has not been well studied. OBJECTIVE The purpose of this study is to estimate the prevalence of undiagnosed asthma in a specific population of patients presenting to an Otolaryngologist with symptoms of allergic rhinitis. STUDY DESIGN Prospective cohort study. METHODS Patients presenting with symptoms of allergic rhinitis to two tertiary care Rhinology practices in Northern Alberta were asked to undergo allergy skin testing, serum IgE quantification, and pulmonary functional testing. Patients with previous asthma screening or known history of reactive airway disease or asthma were excluded. RESULTS 107 patients with allergic rhinitis symptoms were recruited between September 2010 to January 2013. Patients predominantly had perennial or persistent rhinitis (64.5%) with moderate-severe symptoms (50.5%). While only 14.9% of patients had abnormal IgE levels, 68.8% had positive skin testing. Abnormal pulmonary function tests were obtained in 39.1% of patients and 26.1% of patients were diagnosed with asthma. CONCLUSIONS There is a high prevalence of undiagnosed asthma in patients presenting to tertiary Rhinology care with moderate to severe allergic rhinitis symptoms. Screening lung function testing should be considered in this patient population.