Allergic rhinitis can be seasonal or perennial. It is an allergic inflammation of the nasal airways that occurs when an environmental allergen, such as pollen or mold, is inhaled by an individual with a sensitized immune system. This type of allergic rhinitis is frequently referred to as hay fever., , , , Pollen is a cause of hay fever for many people, so the amount of pollen in the air will affect whether symptoms develop or not in many cases. The types of pollen that cause hay fever vary de...