Food allergies and sensitivities: testing

What do I do if I think my child may be reacting to a food?

Pay a visit to your GP, nutritionist or dietitian to confirm your suspicions and then if needed, he or she will refer you both off for testing. Diagnosis of a food allergy will generally involve a thorough case history (family history, medical history, diet and so on), physical examination and, in many cases, diagnostic testing as well dietary trials.

Be careful with the advice of well-meaning friends and family or even professionals who don’t specialise in child health. Your child’s growth and development depend on an accurate diagnosis and comprehensive dietary and lifestyle advice. Most specialists will ensure you go home with a bundle of recipes, fact sheets, helpful hints and lists of books and supportive groups and websites.

Don’t be tempted to reduce a child’s diet. They are experiencing such a fast growth rate and it is essential they maintain a varied, healthful diet to meet their needs. Where a change in diet is required, your health care professional will replace any eliminated foods to ensure a nutrient-sufficient diet is maintained.

What can we expect if we went for testing?

While testing for true food allergies is somewhat more conclusive than that of food intolerance, there is still a degree of uncertainty in many cases. Testing is one piece of the puzzle and is used in conjunction with a review of medical history. The following are common tests that may be carried out:

1. Skin prick tests – This involves adding suspected and common allergens to the forearm or back. The area of application is carefully pricked. Reactions are observed. Results are not always 100% accurate, hence testing is just one part of the testing jigsaw. Skin prick testing is generally opted over allergen specific IgE (known previously as RAST tests) testing as it is easy to conduct, less expensive, less invasive and results are available quickly.
2. Allergen-specific IgE blood tests (RAST) – allergen specific IgE tests, being more invasive, expensive and time consuming, are useful when skin testing has been inconclusive. This form of testing may be used when skin prick testing isn’t possible. It involves obtaining a sample of blood and then measuring levels of certain immune substance called IgE.
3. Elimination diets and challenge testing – Elimination diets are useful in tracking down food culprits so that they can be eliminated from the diet (temporarily or permanently). It can be a time consuming process. Only selected foods and fluids can be consumed initially, and assuming symptoms improve, then one food is added at a time (slowly) with the occurrence of symptoms noted in relation to the food introduced at that time. It is helpful to have a record (diary) of the diet over this period. Such diets must not be undertaken without professional advice. In particular, food challenges should be performed by a suitably qualified health specialist, given the risk of serious reaction such as anaphylaxis.

The main message is that you will be in good hands and that these tools will help guide you to cope with any allergies or intolerances for your little one’s best health. Nothing is too small to investigate when it comes to your child’s health.