A food allergy is an abnormal immune reaction to food. It can present as hives and skin swelling; difficulties breathing; vomiting, diarrhoea; dizziness/collapse. In some people, food allergy causes a life-threatening reaction known as anaphylaxis.
Confirmed food allergy affects up to 3% of adults; self-reported food allergy is much more common and often confused with food intolerance where the immune system is usually not involved.