What should you know about IgG food allergy?

IgG antibodies can reflect exposure to a food rather than an allergic reaction. A positive panel may therefore identify foods you eat regularly without showing that they cause harm. Food allergy is an immune reaction that can cause symptoms such as hives, swelling, vomiting, wheezing, or an itchy throat soon after eating. A severe reaction can become anaphylaxis. An IgG result cannot reliably separate allergy from tolerance, and a negative result does not explain every food-related symptom.

A clinician considers the timing and pattern of reactions, the food involved, other illnesses, and medicines. They may recommend validated skin-prick or specific IgE testing, sometimes followed by a supervised food challenge. See Food Allergy and Allergy Testing for context.

Do not remove many foods solely because a commercial IgG panel lists them. Broad restriction can make meals difficult and may reduce nutritional variety. Keep a record of what you ate, the amount, when symptoms began, and what happened. Arrange a review with a clinician who can assess suspected Food Allergy and decide whether targeted testing is useful. Until reviewed, avoid any food that has clearly caused a previous immediate reaction, and ask about a written emergency plan if you have had swelling, breathing trouble, or collapse.

Call emergency services immediately for trouble breathing, throat or tongue swelling, faintness, confusion, or rapidly spreading symptoms after eating. These can be signs of Anaphylaxis. If prescribed an adrenaline injector, use it according to your emergency plan and seek emergency care. Arrange prompt medical advice for repeated vomiting, persistent hives, or a reaction that is becoming more severe. An itchy throat after food deserves assessment, especially when it occurs with swelling or breathing changes.

Ask which symptoms and timing support a genuine allergy, whether any food should be avoided now, which validated test fits your history, and how to recognise and manage a future severe reaction.