Allergic rhinitis and asthma: from the link to emerging therapies.

Epidemiological evidences and clinical as well as experimental observations have suggested a link between rhinitis and asthma. This relationship between rhinitis (and sinusitis) and asthma also involve other aspects, such as viral infections and bronchial hyperreactivity. These have been further confirmed by functional and immunological evidences, challenge studies of the nose and the bronchii, and, indirectly, by observing the therapeutic effects of drugs used mainly for rhinitis on the symptoms of asthma. Therefore, the present article is a review of the most relevant experimental results, so far provided, supporting the 'One Airway One Disease' concept, the possible mechanisms involved in this link and emerging therapeutic strategies like leukotriene receptor antagonists.