Let’s start right from the beginning:
What is a food challenge?
Sometimes a skin prick test and/or a blood test does not give a doctor enough information to know if a patient is truly allergic to a particular food. A food challenge, sometimes known as an Oral Food Challenge (OFC) or just oral challenge, is the best way for an allergist to evaluate a patient’s allergic response.
Food challenges are sometimes used to diagnose a food allergy. While skin prick tests and blood tests are great indicators of a food allergy, they cannot help a doctor or patient understand their individual risk of a reaction. Only the Oral Food Challenge can demonstrate a person’s true sensitivity to a given food.
Oral challenges are also helpful in determining whether a patient has outgrown a food allergy. Doctors will suggest an oral food challenge when they believe an individual may successfully tolerate a food they previously tested allergic to.
How does it work?
For a variety of reasons, doctors may want to test a patient against his/her food allergy. In a doctor’s office or hospital setting, food is given to that patient every 15 to 30 minutes – beginning with a very small amount and increasing with each “dose”. The patient is observed and medically evaluated at each interval to check for symptoms of a reaction. Feeding typically continues until a full portion of that food is consumed safely.
If the doctor sees symptoms of a reaction, he/she will stop the test. If, on the other hand, there are NO symptoms, your doctor may rule out a food allergy and discuss ways to manage that food going forward.
Where do you go for a food challenge? Can I do it myself at home?
OFCs are ONLY conducted in a doctor’s office or hospital setting and should only be done under a doctor’s supervision. It is critical that the patient be checked by a doctor or nurse at each stage in the process for a reaction. And, should such a reaction occur, the medical staff are on-site ready to respond immediately.
You SHOULD NEVER conduct an oral food challenge at home.
How safe are OFCs?
Food challenges have an excellent safety record because allergists and trained professionals follow medical standards and procedures for the test and they are prepared to handle any emergency that arises. Thousands of OFCs have been performed worldwide safely.
Be aware, there is a risk for an allergic reaction with this test which is why it MUST be performed by a doctor in a medical setting. The most common reactions in an oral challenge are mild skin and stomach reactions which are typically treated with antihistamines. Allergists are prepared to use epinephrine and other medications in the unlikely event that a more severe reaction occurs.
That said, most doctors recommend an oral challenge when they believe the patient will pass this test. They try to set their patients up for success.
How do I prepare for a food challenge?
1. Remind yourself and/or your child that there is no “passing” or “failing” an oral challenge – there are only results. In this way, you can keep anticipation and disappointment in check. [But feel free to go crazy celebrating if you’re able to add another food to your diet later!]
2. Have a conversation with your allergist’s office about what to bring and how to prepare it. Allergists typically recommend how to prepare the food you are testing for. For example, when my son tested for soy, we brought soy milk; for wheat, we brought toast; for milk and egg, we were instructed to make muffins and French Toast using a particular recipe. Depending on your child’s age and particular tastes, the allergist may be able to alter the recommended food to make it more palatable.
3. You will need to stop taking antihistamines as well as some other medications for at least one week prior to your appointment. Discuss this with your doctor’s office for further instructions. ALWAYS take emergency medication (such as a rescue inhaler or epinephrine) should you need it leading up to the oral challenge. Oral challenges can be postponed if need be.
4. Prepare for the day. Oral Food Challenges often take several hours. Think about what will amuse you and your child for that period of time. Consider coloring books, small lego sets, matchbox cars, books, a portable DVD player or iPad. And, yes, that means you might arrive with a giant “tote bag of fun,” looking like you’re ready to move into the doctor’s office like I did.
5. Write down questions about the possible results of the test as you go along, You should have a chance to discuss the results after the challenge has finished. Some questions you may wish to ask if you can add a new food:
- What do the results tell us about my allergy?
- Are there any limits to the quantity/variations of this new food we can add?
- Can we add this food in its baked AND unbaked forms?
- What symptoms should I look for over the next few hours and days?
- Does this alter my Emergency Action Plan? Can you fill out a new plan so that I can copy this information for the school nurse, after care, babysitter, etc?
For those of you who have experienced an oral challenge: what advice would you add?