This study is aimed at validating key therapeutic targets and biomarkers associated with allergic rhinitis. The therapeutic target expression will be investigated after a 7 day course of corticosteroid treatment followed by allergen challenge.

Inclusion criteria:

• No signs or symptoms of rhinitis outside of the relevant airborne allergen season.

Exclusion criteria:

• History or current evidence of an upper or lower respiratory infection or symptoms (including common cold) within 2 weeks of baseline assessments.
• Symptoms of rhinitis at inclusion indicated by total VAS score of >40 for the combined symptoms scores for blockage, rhinorrhoea, sneezing, itching) or a single symptom with a VAS score >20.
• Subjects not showing a nasal response to allergen concentration =< 10,000 BU/ml.
• Subjects with positive skin prick test for Dust House Mite.