What is the definition or description of: allegra (fexofenadine) allergy?

Allegra (fexofenadine) allergy: Allegra is a brand name for a medication used to treat hay fever and allergy symptoms. It is a type of anti histamine that reduces or blocks histamine. Histamine can cause itching, sneezing, runny nose, and watery eyes. Antihistamines stop these allergy symptoms. Allegra belongs to a newer generation of antihistamine medications that produce less drowsiness associated w older drugs like benadryl (diphenhydramine).