Seasonal allergies affect around 20-25% of US adult population or 40-60 million people each year, according to the Allergy and Asthma Foundation of America.

Allergies in general are a physical, hypersensitive immune reaction to an antigen in response to exposure or reaction to a substance. This could be a food allergy, seasonal or other allergy. Some of the most common allergies are pollen, ragweed, animal fur, dust or certain foods. In reaction to the allergen the body produces the chemical histamine, which helps counteract that allergen. Generally, histamine helps the body with functions, like, immune system, communicating messages to the brain and keeping it awake and helps trigger the release of stomach acid. Its main role with allergies is to cause an inflammatory reaction in the body as a red flag of potential pathogens (danger). More specifically, it helps the blood vessels swell so white blood cells can travel and find the pathogen faster. This is a natural and proper response. Enzymes in the body will breakdown histamine afterwards.