Hello, For chronic rhinosinusitis, you must ensure that you have a CT Paranasal sinuses scan to ensure this is the correct diagnosis. The scan will also give us information on the extent of damage to the osteomeatal complex. This will guide treatment. As far as allergic rhinosinusitis is concerned, you need skin prick tests or blood test for allergy (specific IgE test) against aeroallergens such as dust mite, molds, fungal allergens etc to confirm the diagnosis. Long acting antihistamines such as allegra 180mg, nasonex nasal sprays are recommended for 3 months (as a start). Prednisolone is not recommend to treat allergies unless symptoms are very severe, not responding to high dose antihistamines, and when only used for short periods. I hope this helps. Best Wishes.