Food prick allergy test: what to know

During a skin prick test, tiny amounts of selected allergens are placed on the skin, usually the forearm or back, and the skin is observed for a local reaction. The test detects sensitisation, meaning the immune system recognises an allergen. Sensitisation and a real-life food allergy are not identical: symptoms after eating, the timing, the amount eaten and your medical history help determine the meaning. A negative test also needs interpretation if the story strongly suggests allergy.

Tell the allergy clinician about reactions, foods you suspect, medicines, skin conditions and previous test results. Some antihistamines can interfere with skin testing, so ask whether and when to pause any medicine; do not stop prescribed treatment without instructions. Do not deliberately eat a suspected trigger to test yourself. Your clinician may discuss an allergy blood test or, when appropriate and supervised, a food challenge.

Call emergency services immediately for swelling of the tongue or throat, breathing difficulty, wheezing, faintness, sudden widespread hives, or symptoms affecting several body systems after eating. These can be signs of Anaphylaxis and need urgent treatment. A test appointment is not a substitute for an emergency plan. Ask your clinician how to use prescribed emergency medicine and when to go to hospital.

Ask which foods should be tested, what a positive or negative result means for you, whether medicines affect the test, and whether you need an emergency action plan. Discuss how to maintain a balanced diet if avoiding a food and whether a dietitian would help.