The interaction between upper and lower airways in allergic rhinitis

Abstract

Introduction. The pathophysiological connections between allergic rhinitis and asthma are still not entirely understood. To elucidate these connections further, two provocation studies were performed in non-asthmatic allergic rhinitis patients. In the first study, we performed a segmental bronchial allergen provocation in seasonal allergic rhinitis subjects without asthma out of the grass pollen season. An increase in symptomatology was found not only in the lung but also in the nose. This increase in symptomatology was accompanied by a generalized inflammatory response, which was characterized by an increase in eosinophils and interleukin 5 (IL-5) expression, in the bronchial mucosa, the blood and nasal mucosa. In the second study, we investigated the effect of nasal allergen provocation on lower airways in allergic rhinitis patients. Again, an increase in blood and bronchial eosinophils, correlating with the local expression of adhesion molecules with the pulmonary symptom score, was found. Conclusion. Allergic rhinitis is not a local disease, but also influences the bronchial mucosa. It is probable that systemic induction of inflammatory mediators leads to a more generalized inflammatory response. This may explain why local treatment of the nose with anti-inflammatory drugs is also beneficial for the lower airways in allergic rhinitis patients with asthma.