Nonallergic rhinitis (NAR) can be defined as a chronic nasal inflammation whichis not caused by systemic IgE-depend ent mechanisms. It is common and prob-ably affects far more than 200 million people worldwide. Both children andadults are affected. How ever, its ex act prevalence is unknown and its phenotypesneed to be evaluated using appropriate methods to better understand its path-ophysiology, diagnosis and management. It is important to differentiate betweeninfectious rh initis, allergic/NAR and chronic rhinosinusitis, as managementdiffers for each of these cases. Characterization of the phenotype, mechanismsand management of NAR represe nts one of the major unmet needs in allergicand nonallergic diseases. Studies on children and adults are required in order toappreciate the prevalence, phenotype, severity and co-morbidities of NAR.These studies should compare allergic and NAR and consider different age grouppopulations including elderly subjects. Mechanistic studies should be carried outto better understand the disease(s) and risk factors and to guide towards animproved diagnosis and therapy. These studies need to take the heterogeneity ofNAR into account. It is likely that neuronal mechanisms, T cells, innateimmunity and possibly auto-immune responses all play a role in NAR and mayalso contribute to the symptoms of allergic rhinitis.
Important research questions in allergy and related diseases:nonallergic rhinitis: a GA2LEN paper