Allergy testing is not perfect, and sometimes we can see false positives to foods that someone has no history of reaction to or have never ingested. In other times, the reaction could have been related to someone else and a patient or allergist is not sure if the food was the cause. In patients with history of food allergic reactions, sometimes they will outgrow their food allergies. Oral food challenges are ways that your allergist can help determine if you are truly allergic to a food. In many cases, your allergy provider may recommend an oral food challenge.
*What is an oral food challenge?
An oral food challenge, or OFC, is a medical procedure done in the allergy clinic where a food is eaten under medical supervision. Usually, OFCs are “graded” which means the food is eaten slowly, in increasing amounts, over several hours. Patients are monitored for development of any symptoms and treated if an allergic reaction occurs.
*What happens on the day of an oral food challenge?
Usually, patients are told to hold antihistamines prior to the OFC. Your allergy provider will examine you before starting the OFC and your vital signs will be taken before and periodically every 15-30 minutes during the test. The first dose is usually very small and after 15-30 minutes, if there are no symptoms, the next dose is taken. This process is repeated until all doses are taken, which usually equal about 1 full serving size of the food.
*What types of reactions could happen during an oral food challenge?
Because OFCs are done slowly, usually a reaction involves skin symptoms (such as mild hives), stomach symptoms (upset stomach), or mouth symptoms (itchy mouth, itchy tongue). Testing and feeding is stopped whenever there are symptoms. Usually, antihistamines are used for these milder symptoms. If there are more severe symptoms, treatments can include epinephrine or other medications.
*What are the risks and benefits of an OFC?
The risks of OFCs are the possibility for a reaction, including anaphylaxis. However, when done safely in the allergy office, these risks are minimized. The benefits to the OFC involve being able to safely incorporate this food into your diet and knowing without fear that you will not have a reaction. Even if there is a reaction, studies show that this can be beneficial by giving families more confidence to treat and recognize reactions in the future.