Rhinitis can last for hours or indefinitely, depending on the cause of it. For instance, acute rhinitis from a cold will last for only a week or so. Chronic conditions may continue indefinitely. Allergic rhinitis (hay fever) depends on your exposure to the allergen that triggers it; when you are exposed, you have symptoms, and symptoms pass after you get away from the allergen. Granted, sometimes exposure is unavoidable and allergic rhinitis may last all season or all year. No matter how long your rhinitis lasts, treatment can be helpful in making the condition more tolerable.