An oral food challenge is the single best test used to find out if a child is allergic to a specific food. It is dose-graded. This means the child is given small amounts (doses) of the food in question to eat and then watched for signs of an allergic reaction. In rare cases, a child may have a serious reaction, called anaphylaxis (anna-fa-LAX-is).
An oral food challenge is very safe to do under proper medical supervision. Even if your child reacted to the food in the past, you and your child do not need to be afraid. You will be with your child the entire time. The allergy team will closely watch them during the process.
A food allergy can vary in each person. Some children are very sensitive and will react after eating only a small amount of the food. Others may have a higher threshold and not react until eating a larger amount. The results of the challenge will tell you:
- your child’s threshold or level of risk for a reaction.
- what a reaction looks like, if it occurs, and how fast it ends with proper treatment.
- if they have developed tolerance for the food or have outgrown the allergy over time.
- if the food can be added safely back into their diet.
Before The Challenge
- If your child is old enough, tell them:
- they will be safe because the medical team will watch them at all times. If they have an allergic reaction, they will get medicine right away to make them feel better.
- you will always be with them.
- the results may let them eat more foods safely in the future because they may no longer be allergic.
- Your child should be healthy for at least 24 hours before the test. If they are sick, please call the clinic at (614) 722-5803 to reschedule the appointment. For everyone’s safety, your child should not have a fever, cold, runny nose, cough or feel ill.
- The test may need to be rescheduled if your child’s eczema or asthma has worsened during the week or if they have allergy symptoms on the morning of the test.
How to Prepare For The Challenge
Before the appointment, your child should stop taking medicines that could hide early signs of allergic reactions.
- 5 days before, stop oral antihistamines, including:
- cetirizine (Zyrtec®)
- hydroxyzine (Atarax®, Vistaril®)
- loratadine (Claritin®, Alavert®)
- levocetirizine (Xyzal®)
- fexofenadine (Allegra®)
- desloratadine (Clarinex®)
- diphenhydramine (Benadryl®)
- cyproheptadine (Periacton®)
- Day of the test, do not take:
- over-the counter NSAIDs (nonsteroidal anti-inflammatory drugs) for pain and fever, like ibuprofen (Motrin®, Advil®) or naproxen (Aleve®). It is OK to take acetaminophen (Tylenol®).
- albuterol (Proventil®, Ventolin®), levalbuterol (Xopenex®) or rescue inhalers
- Continue giving prescribed medicines, including other asthma medicines and inhalers, eczema creams, ointments and moisturizers, unless the allergy team tells you not to.
- Morning of the test, eat a light breakfast. Your child should come hungry but not starving.
What to Bring
- Your child’s epinephrine auto-injector (Epipen®, AUVI-Q®) for the car ride home. While it is not common for allergic reactions to happen after you leave, it is important to be ready to treat them. If you do not bring this medicine, we may not do the challenge that day.
- Things to comfort or occupy your child during the test, such as books, electronic games and stuffed toys.
- A change of clothes for both you and your child in case your child vomits.
- A snack or other foods your child likes that may help them eat the food being tested. For example, bring a favorite cracker if they are trying peanut butter or allergen-free frosting or jelly if the challenge is to be a baked muffin.
- A safe snack for after the challenge.
How The Challenge is Done
- Prepare to be with us for 3 to 4 to hours; longer, if your child has an allergic reaction.
- Your child will not be hooked up to any kind of machine and can move freely.
- A small amount of the food is given to them every 10 to 15 minutes. More is slowly added, in increasing amounts, until your child can eat a normal amount. The team will watch for signs of an allergic reaction each time your child eats the food.
- After your child eats the last dose of food, our team will watch them for 1 to 2 hours more. If they show no signs of an allergic reaction, then we will know they are not allergic to the food. The challenge is over and you can go home.
Risks and Possible Complications
- It is common for the team to see mild symptoms during the test. If your child is doing well, we will continue to give them more food.
- Your child may have an allergic reaction during the challenge. If we need to treat them for any reason, we will stop the challenge.
- To treat mild symptoms, like itching, rash, coughing or vomiting, your child may be given an antihistamine or other medicine to help them feel better.
- If your child shows signs of a severe allergic reaction, such as trouble breathing or swallowing, repeated vomiting or low blood pressure (passing out), they may be treated with epinephrine. Epinephrine works very quickly to reverse anaphylaxis.
After The Challenge
- Your child should have no problems after they are home. Although rare, it is possible that they could have a late onset or delayed reaction.
- If your child did not have symptoms of an allergic reaction:
- we will remove the allergy information from their medical record.
- your child will be able to eat that food as part of their normal diet.
- share this information with their health care providers and others who need to know.
When to Call The Allergy Clinic or 911
- Call the allergy clinic if your child shows any delayed mild reactions, like itching, rash, coughing or vomiting, after going home on the day of the challenge.
- Treat your child with the epinephrine auto-injector and call 911 for signs of a serious allergic reaction, such as:
- trouble breathing
- trouble talking
- repeated vomiting
- throat tightness
- swollen tongue
- feeling of doom
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