Role of the Central Nervous System in Allergic Rhinitis

Inclusion Criteria: * Patients with a positive skin prick test to grass pollen and with pollen allergic symptoms during the pollen season OR patients with a negative skin prick test and with no allergic symptoms during the pollen season. * Age \> 18 and \< 50 years * Written informed consent * Willingness to adhere to visit schedules * Adequate contraceptive precautions in female patients with childbearing potential Exclusion Criteria: * Current or recent (finished less than 2 years) immunotherapy against grass pollen. * Systemic steroid treatment less than 6 weeks before the inclusion in the study. * Nasal steroid spray, oral leukotriene antagonists or long-acting antihistamines less than 4 weeks before the inclusion. * Presence of purulent secretions in nasal cavity. * Severe septal deviation (septum reaching concha inferior or lateral nasal wall). * Patient is pregnant or breastfeeding. * Patient has any disorder of which the investigators feel at the time of evaluation for participation in the study that this may compromise the ability to give truly informed consent for participation in this study. * Patient is currently enrolled in other investigational drug trial(s) or is receiving other investigational agent(s) for any other medical condition. * No independent medication management in daily life or disability to perform fine motoric handling of medication * Patients with asthma will be excluded. * Patients suffering from claustrophobia