How Does Allegra Work?
Start
When you come in contact with something you’re allergic to, a chain reaction begins inside your body. During this chain reaction, specialized cells release powerful chemicals. Some of these chemicals can trigger swelling of the nasal passages leading to nasal congestion (a “stuffy nose”). Other chemicals, such as histamine, can cause sneezing, itching, and irritation.
Allegra is classified as an antihistamine. Allegra blocks the effects of histamine (hence its classification as an antihistamine). This can relieve allergy symptoms. However, since histamine is not the cause of nasal congestion, Allegra will not help open nasal passages.