Oral Immunotherapy (OIT)
Food oral immunotherapy (OIT) is a treatment for patients who have immediate-type (IgE-mediated) food allergy. Peanut oral immunotherapy (OIT) is offered at AAAI. It has been used for the treatment of common food allergies such as peanut, egg, milk, wheat, soy and tree nuts (eg. almond, cashew, ect). This therapy begins by eating a very small amount of the food (eg. 1/50,000 peanut). In most protocols, there is an initial increase in dosing that occurs in the office over hours. That dose is then repeated once or twice a day at home for ~ 14 doses. Patients then return to the office for a higher dose with 1-2 hours of observation. The higher dose is then repeated at home, once or twice a day at home for ~ 14 doses. This pattern is then repeated 10-20 times, depending on the protocol, until a normal serving dose is reached (eg. ~2 tablespoons peanut butter). A challenge is then performed in the office. A maintenance dose is then eaten every day to maintain desensitization. The food can then be introduced into the diet. If the daily maintenance dose is stopped for a few days, desensitization may no longer be present. OIT is typically started at age 5, although some Allergists are treating younger patients.
OIT is not approved by the FDA. It has been used by a few private practice Allergists across the United States for 5 years, and over 1000 patients have gone through the procedure. The results from these private practices has been published in medical journals. OIT has been performed at academic medical centers as well. However, there are academic and private practice Allergists who do not feel OIT should be offered in a private practice setting. Opponents of private practice OIT do not feel the long term outcomes are ready to recommend its use.
Around 80% of patients who start OIT in private practice are able to reach the goal dose of the procedure (as published for peanut). We cannot say this treatment “cures” food allergy or leads to “tolerance”. There is always the risk of having a systemic reaction (ie. anaphylaxis) with the OIT procedure, even after the goal dose is reached, and the patient is on maintenance therapy. In one study, the likelihood of a systemic reaction during the build-up phase of OIT is higher than strictly avoiding a food and having an inadvertent exposure. Most protocols recommend waiting 2 hours to exercise after each dose during the build-up phase, including an active game of “Wii” or a light jog, as increased body temperature can cause a reaction that would not otherwise occur. Although reactions are significantly reduced once a patient reaches their goal/maintenance dose, but reactions can still occur, and patients still need to have their epinephrine auto-injector present at all times. Less severe reactions such as stomach discomfort may occur and limit progression. Illness or uncontrolled asthma can lead to dose adjustments and an extended duration of time to reach the maintenance dose. In rare cases (<10% of the time), eosinophilic esophagitis may develop. This condition causes inflammation of the esophagus due to food exposure and can lead to stomach pain, reflux symptoms, pain when swallowing food or food even getting stuck in the esophagus. OIT is time consuming and can carry significant costs.
Thankfully, deaths due to food allergy are a rare occurrence. However, the anxiety that comes with the possibility of a severe, allergic food reaction is high for a number of patients and families with food allergy. In addition, there are a number of negative social implications associated with the condition. Food allergy also limits the choices of foods due to an ingredient or potential of cross contamination. These limits can result in higher food bills and decreased quality of life from diminished food choices.
Given greater than 5 years of experience and long term outcomes from private practice patients going through OIT, and the impact food allergy has on patients and their families; the physicians at Allergy and Asthma Associates, Inc. now feel OIT may be viewed as a treatment consideration in patients with food allergies as long as its potential drawbacks and controversy are understood. Patients and their families who have gone through OIT realize there is a risk for reaction during the OIT process, but they like knowing the food is being given in a relatively controlled manner with 2 hours observation after the dosing at home rather than react in an unsupervised environment. And while the risk of reaction once on the daily maintenance dose does not go to 0%, the risk is greatly reduced and offers a level of control that strict avoidance without OIT does not offer. Many who have gone through OIT feel it has been “life changing”.