When allergens—pollen, grasses, dust mites or molds—find their way into your nose, your body goes into attack mode if it's hypersensitive, or allergic. Immune cells release histamines, the chemicals responsible for most of your allergy symptoms. These in turn kick-start inflammation that's intended to keep the allergens from traveling into the body. The inflammation makes sinuses and nasal passages swell and eyes itch. Histamines also stimulate the nasal passages to release fluids, resulting in a runny nose and itchy throat, and cause sneezing, another attempt to send the allergens packing. Many of the foods that may help reduce allergies work by reducing inflammation or calming the immune system.