What is OIT? Oral immunotherapy (OIT) is the process of giving small amounts of a food allergen (the problem food) in increasing amounts to someone who is allergic. The purpose is to desensitize them, or make them less reactive to the food. The idea of OIT is to start with an amount of allergen that would not be expected to trigger an allergic reaction and gradually build up to larger amounts that could provide a layer of protection in case of an accidental ingestion. The patient who is allergic takes the small dose (determined by the doctor) of the allergen every day. The dose is gradually increased over a period of 6-12 months and then taken consistently to maintain desensitization (maintenance treatment). The first dose of each increased amount is done under medical supervision to make sure that the patient tolerates it.
Why do OIT? The goal of immunotherapy is to prevent reactions or decrease the severity of a reaction if the person accidentally ingests their allergen. Once a patient reaches maintenance treatment, it is expected that they would be protected from small amounts of allergen contamination, such as the amount that may be in a packaged food with precaution allergen labeling (e.g. “may contain”), or from cross-contact in a restaurant, making eating out safer.
Can OIT help someone outgrow their allergen? OIT is not considered a cure at this time, and the patient is not expected to have the ability to consume their allergen in unlimited amounts. If the patient tolerates the initial OIT protocol, increasing doses to reach a more natural inclusion of the allergen in the diet can be considered. Otherwise, the patient should continue to avoid the food(s) that they are allergic to outside of their OIT doses and carry their epinephrine auto-injectors.
Does age matter when starting OIT? OIT can be started at any age, however data suggests that OIT in young children (age 3 years old or younger) may be more effective, and they may have less side effects. In other words, the earlier OIT is started the more likely there will be better long-term outcomes.
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 on maintenance treatment than they did prior to starting treatment.
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 an epinephrine auto-injector, such as difficulty breathing, wheezing, severe abdominal pain, vomiting, or anaphylaxis, are possible but uncommon (occurring in less than 5% of patients in clinical trials). Infrequently, patients experienced 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 are typically reversible and resolve if OIT is stopped.
What does the OIT schedule 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 1 hour (more if the patient has symptoms) following the dosing of the allergen. Visits are generally 1.5 to 2 hours in length and occur every 4 weeks (approximately). The up-dosing period generally takes about 6-12 months to get to the maintenance dose (sometimes longer if there are illnesses, vacations, side effects, etc.). Once the patient is tolerating their maintenance dose, the visits space out to about once every 6-12 months.
What happens at the OIT office visits? At each OIT visit, the nurse will bring the patient in and do vital signs 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 has at least two epinephrine auto-injectors with them at the visit. The doctor or nurse practitioner will then do a physical examination of the patient and discuss how the treatment doses have been tolerated at home. If appropriate to increase the patient’s dose, the patient will ingest 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 hour (longer if the patient has symptoms). Skin prick testing and allergen-specific IgE lab testing will be done to monitor the patient’s allergy markers at baseline and approximately every 6 to 12 months.
What is my responsibility as the parent/guardian? It is very important that the patient and their parents/guardians are committed to this process. The patient and parent/guardian must be diligent about mixing and taking their prescribed dose each day and coming in for up-dosing during the build-up phase. Instructions will be given about how to give OIT doses that must be followed closely. It is the responsibility of the parent/guardian to contact the Food Allergy Immunotherapy Clinic personnel 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 essential that the patient continue to avoid their allergen(s) outside of their OIT doses and have access to their epinephrine auto-injectors at all times.
What challenges does OIT present? The most challenging part of OIT is finding time and consistency in giving the day-to-day dosing. The child must take their dose with a parent/guardian who feels confident monitoring them for 2-3 hours afterwards. Doses should not be given right before going to school, which means most doses are given in the evening at dinnertime. During monitoring, the child should not be doing extraneous exercise, sweating, or taking hot baths/showers. Exercise and heat can lower the threshold for having symptoms or side effects after taking OIT doses. Busy families should consider if this daily commitment is right for them.
What happens if I stop OIT? At this time, OIT is not considered a cure. A maintenance dose should be taken indefinitely to maintain protection. Improvements in OIT based on research may change this advice in the future.
What are the next steps if I am interested in OIT for 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 if you are interested or would like more information about OIT, 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.