Efficacy and Safety of Nasal Filters on Seasonal Allergic Rhinitis (Hay Fever)

Inclusion Criteria: * History of seasonal allergic rhinitis (SAR) for a minimum of 2 years before study entry. Documented by a positive skin test within 12 months of study enrollment. * Written informed consent * Reliable anticonception for fertile women * Must be able to complete the study * Forced Expiratory Volume at one second (FEV1) higher than 70 % of predicted value * Positive grass immunoglobulin-E (IgE) blood sample equal to or higher than 3,50 kU/L Exclusion Criteria: * Positive pregnancy test for fertile women * Asthma unless mild and only occurring in relation to the grass pollen season as assessed by the investigator * Inadequate washout periods in regards to Environmental Exposure Unit (EEU) appointments (intranasal or systemic corticosteroids (1month), intranasal cromolyn (2 weeks), intranasal or systemic decongestants (3 days), intranasal or systemic antihistamines (3 days), loratadine (10 days)) * Rhinitis medicamentosa * Use of long acting anti-histamines * Documented evidence of acute or chronic sinusitis as determined by individual investigator * FEV1 lower than 70 % of predicted value * Subjects with perennial allergic rhinitis (PAR) to e.g. house dust mites, cats, dogs moulds unless symptom free * Allergic rhinitis requiring medication caused by allergens other than grass unless symptom free * Subjects with nasal conditions likely to affect the outcome of the study in the opinion of the investigator, i.e. anterior nasal septum deviation, nasal septum perforations, nasal polyps, chronic nasal obstruction or other nasal diseases * Receipt of immunotherapy with grass pollen within the previous 10 years * Women who are breastfeeding