Hi dear, since when are you having this allergy? Is there any construction going on near your house? Any other dust issues? Take more of fruits both fresh and dry n raw vegetables as in salads as they build up your resistance.
Next Steps
Is air conditioner being constantly used or used for long at nights? What about maintenance of hygiene at home? Changing of bedsheets, cobweb cleaning, mopping, dusting, sweeping etc.
Health Tips
Try to avoid consuming cold items or items directly from the fridge. Do perform certain physical exercises on a regular basis.