[Asthma, allergic rhinitis, sinusitis. Concept of the "unified respiratory tracts"]

Epidemiological studies indicate that allergic rhinoconjunctivitis (ARC) is an important risk factor for bronchial asthma. Both asthma and ARC have now been recognized as inflammatory diseases with similar manifestations in the mucous membranes of the upper (nose and paranasal sinuses) and lower respiratory tract (bronchi). Recent studies show that the deposition of allergen into the lower respiratory tract leads to increased inflammation of the upper respiratory tract, even if the patients are only suffering from ARC. These and other findings indicate that allergic diseases have a systemic component, which might be insufficiently targeted with local therapy. It is currently believed that the impaired function of the upper airways due to ARC causing nasal obstruction, retention of secretions, and disturbed conditioning of the inspired air plays an important role in the development of lower airway symptoms. Studies indicate that treatment of the upper respiratory tract inflammation not only reduces the manifestation of allergen-associated symptoms in the lower respiratory tract, but might also have preventive properties if applied early. ARC should no longer be viewed as a harmless disorder but as the early manifestation of a potentially progressive systemic disease and be treated as such.