Although food allergy is a growing public health issue in the U.S. for people of all ages, including 1 in 13 children, many people continue to misunderstand the difference between food allergy and food intolerance. Knowing the difference and recognizing the signs and symptoms of an allergic reaction can protect and save someone’s life.

From mild to severe

A food allergy is an overreaction of the immune system to a specific food protein. When the food protein is ingested, it can trigger an allergic reaction that may include a range of symptoms from mild to severe. Reactions can be severe and life-threatening.

Food intolerances, on the other hand, occur when the body has trouble digesting a food. Intolerances can cause upset stomach, but do not involve the immune system, and cannot trigger anaphylaxis, a potentially life-threatening reaction. 

"Suspected food allergies should always be evaluated, diagnosed, and treated by a qualified medical professional, such as a board-certified allergist."

Allergic reaction symptoms typically appear within minutes to several hours after eating a problem food, and mild reactions have the potential to worsen quickly and become severe.

Importantly, past reactions also do not predict future reactions, so someone with a history of mild reactions may still be at risk for a serious reaction if they eat a food to which they are allergic.

Know the reaction

Mild food allergy reaction symptoms may include: hives (reddish, swollen, itchy areas on the skin); eczema (a persistent dry, itchy rash); redness of the skin or around the eyes; itchy mouth or ear canal; nasal congestion or a runny nose; slight, dry cough; odd taste in mouth and uterine contractions.

Severe symptoms may include: obstructive swelling of the lips, tongue, and/or throat; trouble swallowing; shortness of breath or wheezing; turning blue; drop in blood pressure; loss of consciousness; chest pain; weakened pulse; and sense of impending doom.

Suspected food allergies should always be evaluated, diagnosed, and treated by a qualified medical professional, such as a board-certified allergist.

If you or someone you know may be experiencing anaphylaxis, it is important for epinephrine to be administered as a first-line treatment, and to go to the emergency room immediately for follow-up care and observation. About 25 percent of patients have a second wave of symptoms, referred to as a biphasic reaction, one to several hours after their initial symptoms have subsided.