It is characterized by sneezing, congestion, itching and dripping of the nose and itchy, watery eyes. Common allergens associated with allergic rhinitis are dust mites, pollens from weeds, grasses and trees, animal dander and molds. Allergic rhinitis may be seasonal or perennial. Seasonal allergic rhinitis, sometimes referred to as hay fever, affects nearly 70 million people around the globe. Causes of Allergic Rhinitis Chemical substances, such as histamine, are normally stored in mast cells found in tissues of the body, including the nose, eyes and skin.
Allergic people form antibodies, called IgE, against pollens and other allergens.
The antibodies attach to mast cells and combine with the allergen to cause the release of histamine and other chemicals from the mast cells. These chemical substances cause the allergic responses of itching, sneezing, congestion and dripping nose. Allergic rhinitis often appears before the age of 20 but may be diagnosed as early as the first year of life, particularly if there is a history of maternal allergy or if the mother is a heavy cigarette smoker. An allergist will take a thorough patient history and conduct skin testing to determine which specific allergens are triggering reactions. Once someone is aware of the substances causing their symptoms, avoidance of triggers is very important.