Allergies are the sixth top cause of chronic illness from the U.S. More than 50 million Americans suffer from allergies every year, according to the CDC. Allergies can normally not be prevented; allergic reactions can, in case you understand the source.

The definition of an allergy and an abnormal response to something which normally happens in the surroundings. And the most reliable way to differentiate an allergy from a non-allergic condition would be really a skin or a blood test, Dr. Tania Elliott, spokesperson for the American College of Allergy, Asthma, and Immunology (ACAAI).

A general rule is: If the allergen is something you breathe, your response will usually influence the eyes, lungs, and nose. If you consume the allergen, the indicators are most likely to appear in and around the mouth, intestines, and stomach.

If you are allergic to food, you will likely have problems, redness, and itchy skin, Dr. Elliott says. If it is a severe allergy, trouble breathing and throat final are common. In case the origin is ecological, then you will probably encounter itchy eyes, runny nose, and itching, she adds.