Food challenges are special tests that confirm whether your child currently has or may have outgrown a food allergy. Once your child has undergone allergy testing for a food allergy, the food challenge can be done to demonstrate that the tests were relevant. More commonly, the food challenge can be done to show that the food allergy has gone away. Food challenges are also done to introduce highly allergic foods to young children in the hopes that early introduction will prevent a food allergy from developing.
During a food challenge, your child will be asked to consume increasing doses of a food that is believed to cause an allergic reaction. If your child has a reaction during the food challenge, he or she will receive immediate treatment. The test usually lasts a few hours.
Food challenges provide more in-depth information than the skin tests or blood tests that are commonly used to diagnose allergies. This can be helpful if your child tests positive for an allergy to a food that he or she has never consumed. It can also clarify results if your child’s tests show an allergy to a food that has not caused an allergic reaction in the past. A food challenge can help determine if your child has outgrown a previously diagnosed food allergy.
Your child’s doctor may recommend a food challenge if your child’s previous allergic reactions to a food include symptoms such as:
Avoid giving your child any antihistamine medicines the week of the food challenge. Many over-the-counter cold or cough medicines may contain antihistamines. Check labels carefully before giving these medicines to your child. If your child takes prescription or over-the-counter allergy medicines, these will also need to be stopped the week prior to the challenge. Asthma maintenance medicines may be taken the week before the challenge. If your child needs to use a rescue inhaler more frequently in the week prior to the challenge, you may need to call the doctor to reschedule the appointment.
If your child is sick, has a severe eczema flare-up/rash or is recovering from a recent asthma flare-up that occurred within the past two weeks, you will also need to call your child's doctor to reschedule the food challenge. Allergic reactions may be more severe under these conditions, so it is safest for your child to postpone the challenge.
Your child should not eat anything after midnight the night before the food challenge or after breakfast if the challenge is scheduled for an afternoon. During this time, you may give your child clear liquids like water, apple juice, iced tea, sports drinks, popsicles or Jell-O. If your child is breastfeeding, he or she may continue prior to the challenge.
Prior to the appointment, a member of your child's care team will contact you to let you know what challenge food you need to bring and how to prepare it. The morning of the food challenge, bring in the challenge food and a “mixing food” as instructed by the staff, including the challenge food’s original container or packaging. The mixing food should be a food your child likes to eat, and the challenge food will be added to the mixing food. These mixing foods can be pudding, grape juice or yogurt.
Since only one challenge food can be tested at a time, do not bring food that contains any of your child’s other allergens. You should also bring clear liquids for your child to drink during the challenge as well as any toys or books he or she may need to stay entertained. The food challenge will last a few hours. You may also want to bring a change of clothes in case of vomiting.
At check-in, you will need to sign a consent form for the food challenge. After you check in to the appointment, your child will undergo a brief physical exam. He or she will be given increasing doses of the food with 15 minutes in between each dose to check for reactions. Your child will be monitored for an additional hour after the last dose or for an additional two hours if there was a reaction.
If your child should experience a reaction to the food challenge, the clinical staff will be on hand to provide immediate treatment. If a reaction occurs, this means your child should continue to avoid that food. If no reaction occurs, the allergy specialist will provide instructions on how to best introduce the food into your child’s diet.
Food challenges can be confusing for children because they are being asked to eat a food that they have been taught to avoid in the past. You can help by encouraging and comforting your child and by explaining that the food challenge is a safe time and place to eat the challenge food.
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