Infant food allergy tests: what parents should know

A clinician may consider a skin-prick test or a blood test for food-specific IgE when symptoms suggest an immediate-type reaction. Results show sensitisation, which means the immune system recognises a food; they do not, by themselves, prove that eating the food causes symptoms.

The doctor will ask what the baby ate, how much was eaten, how quickly symptoms appeared, and what happened when the food was avoided. Hives, facial swelling, vomiting, coughing, wheezing, or sudden changes after a particular food may guide the assessment. A negative result does not explain every digestive or skin problem, and a positive result can occur without a clear clinical allergy.

Some reactions are delayed or do not involve IgE, so a standard skin or blood test may not identify them. If the diagnosis remains uncertain, an allergy specialist may recommend a planned oral food challenge. This is done with medical supervision and should not be attempted at home.

Keep a record of foods, amounts, preparation, timing, symptoms, and medicines given. Take photographs of visible rashes if they fade before the appointment. Do not remove several foods from an infant's diet without clinical guidance, because unnecessary restriction can affect nutrition and make feeding harder.

Arrange assessment with a paediatrician or allergy clinician, especially after a reaction involving breathing, swelling, repeated vomiting, or more than one body system. The clinician can explain whether testing is appropriate and how to introduce or avoid foods safely. Allergy testing is part of a wider evaluation, not a substitute for it.

Seek emergency help immediately if an infant has trouble breathing, noisy breathing, swelling of the tongue or throat, marked paleness or floppiness, faintness, or symptoms affecting several body areas after eating. These can be signs of anaphylaxis, a serious allergic reaction.

If an adrenaline auto-injector has been prescribed, use it according to the child's emergency plan and call emergency services. Do not wait for an allergy test result, and do not rely on an antihistamine for breathing or circulation symptoms. An infant with ongoing vomiting, rapidly spreading hives, or a sudden change in responsiveness also needs urgent assessment.

Ask which test matches the reaction pattern, whether the baby should avoid a specific food while waiting, and how to maintain safe nutrition. Ask what symptoms should prompt emergency treatment, whether an adrenaline auto-injector is needed, and when supervised reintroduction or a food challenge could be considered.