On the average, a person could experience several allergic reactions to one or more things. This happens when we breathe in something that is usually harmless and our immune system (the body's barrier against viruses and bacteria) classifies it as harmful and attacks. These are the allergens that we need to avoid exposure to. The hard part is, it is difficult to avoid allergens if we don't know specifically what we are allergic to. Much harder still, allergens are everywhere. They can be in the form of plant pollens from trees, grasses, and weeds, dust mites, animal dander, cockroaches, mold, chemicals, and so forth. It makes it thrice as hard to avoid because pollen and mold may become airborne and can travel easily for miles.

Food allergies or food intolerances affect nearly everyone at some point. People often have an unpleasant reaction to something they ate and wonder if they have a food allergy. Food allergies occur when your immune system makes a mistake. Normally, your immune system protects you from germs and disease. Food allergies result from an abnormal response after eating certain foods. An “allergen” is the part of the food which is responsible for producing the allergic reaction.

Allergic reactions can occur in the skin, respiratory system or gastrointestinal tract, causing swelling, hives, sneezing, nausea, abdominal pain, wheezing, shortness of breath or a drop in blood pressure.