What is it?
A food allergy is when the immune system responds to an allergen (an ingredient that is usually harmless) in food. This triggers a reaction, which can range from mild to severe. A mild allergic reaction can cause hives, swelling, itching, redness, discomfort or pain. A severe allergic reaction (anaphylaxis) is a medical emergency.
A food intolerance is more common than a food allergy. It happens when the body has a reaction to eating a food or drink. Symptoms are similar to a food allergy, but an intolerance does not cause anaphylaxis.