What is OIT? Oral immunotherapy (OIT) is feeding small amounts of a food allergen (such as peanut) in increasing amounts to someone who is allergic, in order to desensitize them, or make them less reactive to the food. The idea is to start with an amount that is so small that it should not trigger an allergic reaction, and gradually build up to a larger amount that will provide some protection in case of an accidental ingestion. The person who is allergic takes the small amount (determined by the doctor) of the allergen every day, usually mixed in with a semi-solid food (such as yogurt, pudding, or applesauce). The amount is gradually increased over a period of 6-12 months and then taken consistently to maintain the protection. The first dose of each increased amount is always done in the doctor’s office to make sure that the patient doesn’t have an allergic reaction.
Why do OIT? The goal of immunotherapy is to prevent the person who is allergic from having an allergic reaction if they are accidentally exposed to their allergen. This treatment is not considered a cure, and the patient is not expected to have the ability to consume their allergen in unlimited amounts. Patients that choose to do OIT will need to continue to avoid their allergen, read labels, and carry their epinephrine auto-injectors with them at all times.
How Effective is OIT? In clinical trials for peanut allergy, about 80% of patients were able to be desensitized, meaning they were able to tolerate more peanut following administration of the therapy than they did prior to therapy.
What are the Risks or Side Effects of OIT? Most patients will experience mild side effects from OIT. Some frequently seen side effects include: mouth itching, throat itching, mild abdominal pain/cramping, and sometimes a mild rash. Often these symptoms resolve with an antihistamine, or even without treatment. More severe symptoms requiring treatment with epinephrine such as severe abdominal pain, vomiting, difficulty breathing, wheezing or anaphylaxis are possible but uncommon (occurring in less than 5% of subjects in clinical trials). Infrequently, subjects can experience symptoms of an allergic condition called eosinophilic esophagitis (EoE). This condition can cause chronic abdominal symptoms (nausea, cramping, vomiting, abdominal pain) and difficulty swallowing. These symptoms typically resolve upon stopping OIT.
What Does the Treatment Schedule for OIT Look Like? The up-dosing period of treatment takes the longest and is the most intensive part of the therapy. Visits to increase doses require observation for a minimum of 90 minutes (more if the patient has symptoms) following the dose of the allergen, so are generally 2 to 2.5 hours in length and occur every two weeks (approximately). The up-dosing period generally takes about 6 months to get to the maintenance dose (sometimes longer if there are illnesses, vacations, reactions, etc). Once the patient is tolerating their maintenance dose well, the visits space out to about once every 2 to 3 months.
What Happens at the OIT Office Visits? At each OIT visit, the nurse will bring the patient in and do vital signs, height, weight, check their breathing with a peak flow meter (if patient is old enough), and ensure that the patient has not had any recent illnesses or conditions that would make it unsafe to start treatment or increase their dose. The nurse will also ensure that the patient/parent has at least two epinephrine auto-injectors with them at the visit. The doctor or nurse practitioner will then come in to do a physical examination of the patient and to discuss how the therapy has been going at home. If deemed appropriate to increase the patient’s dose, the patient will consume the prescribed dose in 1-2 parts while monitored by the doctor or nurse practitioner. Following consumption, the patient will be observed for a minimum of 1.5 hours (longer if the patient has symptoms). At baseline and approximately every 6 months, we will perform skin test testing and allergen-specific IgE blood testing to monitor the patient’s allergy markers.
What is My Responsibility as the Patient/Parent? It is very important that the patient and their family members are committed to this process. The patient and family must be diligent about mixing and taking their prescribed dose each day and coming in for up-dosing every 2 weeks during the build-up phase. Each patient/family will be given instructions regarding dose administration that must be followed closely. It is the responsibility of the patient/family to contact the food allergy personnel on call if the patient experiences issues with their dose or any events that may interfere with the safety of the administration of their current dose. It is absolutely essential that the patient continue with a diet avoidant of their allergen(s) and have access to their epinephrine auto-injectors at all times.
What Happens if I Stop OIT? At this point OIT is not considered a cure. While research is ongoing about what happens after OIT in stopped, at this time, a maintenance dose will have to be taken daily indefinitely to maintain protection.
What are the Next Steps if I am Interested in OIT for Me/My Child? In order to determine if your child is a candidate for OIT treatment, your child needs to be evaluated by one of the allergists at Rady Children’s Hospital. If your child already has an allergist at Rady Children’s Hospital, please contact them and let them know that you are interested or would like more information, and they can refer your child to the Food Allergy Immunotherapy Clinic. Otherwise, please make an appointment for your child with one of our allergists for an initial consultation by calling Central Scheduling at 858-966-5999, ext. 2; you may need a referral to Allergy from your primary care physician, depending on your insurance coverage.