Purpose of review: The relationship between allergic rhinitis and asthma has intrigued practicing physicians since the turn of the century. Investigations during the past two decades have led to an increased understanding of this relationship.
Recent findings: A growing body of evidence clearly demonstrates that patients with allergic rhinitis, in the absence of asthma, have distinct abnormalities of lower airway function, including alterations in physiology, histology and biochemistry. In addition, epidemiologic surveys have consistently shown allergic rhinitis as an independent risk factor for developing asthma, and that preexisting abnormalities in lung function may predispose to lower airway disease development. Clinical trials show that specific allergen immunotherapy for children and adults with seasonal allergic rhinitis reduces the risk of developing asthma. In patients with established asthma and concomitant allergic rhinitis, several medications have significant effects upon the upper and lower airways, including intranasal corticosteroids, oral antihistamines, and leukotriene receptor antagonists.
Summary: Our understanding of the natural history of allergic rhinitis could lead to improvements in early intervention, potentially preventing the progression of allergic rhinitis to asthma. Aggressive treatment of rhinitis in patients with concomitant asthma may enhance asthma outcomes and quality of life for all patients with these chronic diseases.