What should you know about different food allergies?

An allergy is an immune reaction to a food protein. Common triggers include milk, egg, peanut, tree nuts, wheat, soya, fish and shellfish, although any food can be involved. Some reactions begin within minutes; others develop later. Hives, swelling, vomiting, abdominal pain, an itchy throat, cough or wheezing may occur. An intolerance is different because it does not involve the same immune mechanism, even though it can also cause digestive symptoms.

The same person may react differently on separate occasions. A reaction can become life-threatening when swelling or breathing difficulty affects the airway, or when dizziness and collapse suggest a serious circulation problem. Food labels and accidental cross-contact can make avoidance difficult.

Arrange a clinical assessment after a suspected reaction, especially if symptoms involved breathing, faintness or repeated vomiting. Allergy testing may help identify a trigger, but tests need to be interpreted alongside the reaction history. Do not remove many foods from a child’s or adult’s diet without professional guidance, because unnecessary restriction can affect nutrition.

If a clinician confirms an allergy, learn the avoidance plan, check ingredient labels each time and tell restaurants or schools. Ask whether you need prescribed adrenaline and learn how to use it. Keep an agreed emergency plan accessible.

Call emergency services immediately for trouble breathing, throat or tongue swelling, widespread hives with weakness, repeated vomiting with other body symptoms, confusion or collapse. These can indicate anaphylaxis. Use prescribed emergency medicine according to your plan and do not wait to see whether symptoms settle. A milder isolated rash or mouth itch still deserves medical advice before eating the suspected food again.

Ask which food or ingredient is most plausible, whether testing is appropriate, how to avoid cross-contact, which symptoms require emergency action, and whether family members or carers should be trained in the emergency plan.