How Is Food Allergy Testing Done?

Your provider will start by asking about your child’s symptoms and any other health conditions they may have. The provider also will do a physical exam to assess your child’s overall health.

 

With this information, your provider will choose the allergy tests that are right for your child. This may include one or more of the following tests:

 

  • Skin prick test. With this test, the doctor places a small amount of the food in question on your child’s arm. They then lightly prick the skin so the food goes under the skin’s surface. If your child is allergic to the food, it will cause a slight swelling at the site of the skin prick in about 15 to 20 minutes. Several foods can be tested at one time.
  • Skin patch test. This test checks for delayed reactions to food and requires three visits to complete. Extracts from several foods that may be causing problems are taped to your child’s back for 48 hours. You return several times over the next few days for the doctor to check your child’s skin for reactions. This test may not work with small children since the panels must stay dry and should not be moved.
  • Blood test. Substances in the blood called IgE antibodies show allergic reactions. A sample of your child’s blood is sent to the lab where it is tested for reactions to different foods.
  • Elimination diet. This test starts with eliminating all foods from your child’s diet that may be causing problems. Your child’s doctor will tell you how long to wait before adding foods back one at a time. With each food, you’ll watch for a reaction. If your child has had a severe reaction to a food, your doctor may not recommend this test.
  • Oral challenge test. If the results of other tests are unclear, your doctor may recommend an oral challenge test. Your child will eat a small amount of the food in question while their doctor keeps a close watch for symptoms of a reaction. If no symptoms occur in 15 to 30 minutes, your child eats a slightly larger amount of the food. This continues until your child has eaten the amount of that food they typically would consume. If a reaction occurs at any time, the feeding stops. Your doctor will be prepared to treat any reaction with medications if needed.

 

Your provider will explain how your child should prepare for these tests. That may involve stopping certain medications, such as antihistamines.