What Is an Oral Food Challenge?

An oral food challenge (OFC) is a definitive, medical procedure to determine whether a person can tolerate a specific food. An OFC is done to either confirm or rule out a food allergy. During the food challenge, the allergist will start with very small amounts of the food that are unlikely to trigger symptoms. If you have no significant symptoms, you will gradually receive larger and larger doses. If you show signs of a reaction, the food challenge will stop.

Why Should You Do One?

Allergists recommend food challenges for a variety of reasons. An OFC is helpful to evaluate foods that were removed from the diet based on solely on positive allergy testing-either via skin prick testing or blood testing. This will hopefully allow for expansion of the diet. For example, people will sometimes test positive to all tree nuts on allergy testing without a history of an IgE mediated reaction (such as hives, difficulty breathing, wheezing, immediate vomiting, etc) to these tree nuts; but, the patient may only be allergic to a few of the tree nuts. An OFC would be helpful in this case for further evaluation.

Additionally, an OFC can be helpful to find out if patient has outgrown a known allergy. Most patients will outgrow milk or egg allergies and therefore, food challenges can be helpful to determine if the patient has done so.

Furthermore, a challenge is recommended for Food Protein Induced Enterocolitis Syndrome (FPIES) reactions, as allergy testing is not a helpful modality in this type of reaction. FPIES is a rare type of food reaction (non-IgE mediated) that affects primarily the gastrointestinal symptoms. Patients will have repetitive, severe vomiting that can lead to dehydration 2-4 hours after ingestion, although can occur earlier or later. The most common FPIES food triggers in children are cow’s milk, soy, rice and oats, but can occur with any food. Most children will outgrow this reaction and therefore, an OFC is recommended under medical supervision to determine if the child has outgrown it.

Preparing for the Food Challenge

• If you or your child are sick, please reschedule food challenge to when you are feeling better. Symptoms include difficulty breathing, rashes/hives, upset stomach, abdominal pain, increased runny nose or congestion, or other concerning symptoms
• Do not take antihistamine medications such as Allegra (fexofenadine), Claritin (loratadine), Zyrtec (cetirizine), or Xyzal (levocetirizine) 3-5 days before challenge
• Stop taking H2 blockers/acid medications such as Pepcid (famotidine) 3 days before challenge
• Stop Combination medications such as over the counter cough and cold preparations as they often contain antihistamines
• Do no take Benadryl (diphenhydramine) 1 day prior to challenge
• You can take your daily asthma inhalers/medications including Singulair or montelukast
• Make sure to have an appetite prior to the food challenge. This may mean skipping a meal or having a small amount

What Happens If You Have a Reaction During a Food Challenge?

“Failing” a food challenge is not a bad outcome and should not be viewed as a negative. Oral food challenges are the gold standard for assessing food allergies and thus reactions confirm you or your child’s food allergy. Therefore, the food still needs to be avoided.

It also can be learning opportunity for how we treat reactions ranging from mild to severe/anaphylaxis and thus allow parents and children to be more comfortable with treating symptoms. This will hopefully improve quality of life and reduce fears or anxiety. Food is stopped at the onset of symptoms.

Do you or your family members have food allergies? Allergy Associates of Utah is an allergy, asthma, and immunology specialty clinic serving the greater Salt Lake City, Utah area with 2 convenient locations in Murray and West Jordan. Led by specialists Andrew Smith, MD, MS, and Tara Sarin, MD, the practice strives to help people of all ages and background achieve success. Request an appointment by phone or online at either Allergy Associates of Utah location for expert allergy and immunology care today.