This article is part of our Food Allergies resource center, covering all aspects of food allergies diagnosis, treatment, and management.
What Oral Immunotherapy Is
Oral immunotherapy (OIT) is a medical treatment for food allergy in which a person consumes gradually increasing amounts of a food allergen under clinical supervision, with the goal of raising the threshold at which a reaction occurs. It is a desensitization process, not a cure — it modifies the immune response to an allergen without eliminating the underlying allergy. OIT requires a significant ongoing commitment: daily maintenance dosing must continue to preserve the desensitization. This page is distinct from the broader allergy treatment overview and from the sublingual immunotherapy page, which covers a different delivery route primarily used for environmental allergies.
Desensitization Versus Sustained Unresponsiveness
Desensitization — the protection OIT provides while maintenance dosing continues — is the primary outcome currently achievable for most patients. A subset of individuals achieves sustained unresponsiveness, meaning some tolerance persists after stopping daily doses, but this outcome is not guaranteed and cannot be predicted reliably in advance. Clinical trials measure protection at defined time points and doses, and results should not be extrapolated to mean that OIT allows unrestricted consumption of the allergen or that protection continues indefinitely without dosing.
FDA-Approved Products and Clinical Protocols
Palforzia is the only FDA-approved OIT product in the United States as of the time this page was written. It is a peanut allergen powder approved for reducing the frequency and severity of allergic reactions in patients ages 4 through 17 with a confirmed peanut allergy. It is administered under medical supervision and used with ongoing daily doses at home. OIT protocols for other foods — milk, egg, tree nuts, wheat — are used in allergy practices and research settings but are not yet FDA-approved standardized products. Protocols vary between clinical programs. Discuss the specific options available at your clinical center with your allergist.
The Treatment Process
OIT typically progresses through three phases. Initial escalation begins in a clinic under medical supervision, where the starting dose is established and the patient is observed for reactions. During the buildup phase, the dose is gradually increased at intervals — typically every one to two weeks in clinic, with daily dosing of the same amount at home between visits. The maintenance phase begins once the target dose is reached; the patient continues taking this dose daily. The entire process can take months to more than a year, depending on the protocol and the individual's response.
Reactions and Adverse Effects
Reactions during OIT are expected and managed as part of the protocol. Mild reactions — oral itching, stomach discomfort, nausea — are common and usually resolve without treatment. More significant reactions including vomiting, hives, or anaphylaxis can occur, particularly during dose increases or in certain situations. Epinephrine should always be available during OIT doses and when taking daily maintenance doses at home. Doses should not be taken when the patient is acutely ill, has uncontrolled asthma, has exercised vigorously within a few hours, or under other conditions specified by the treating allergist — these situations can lower the reaction threshold.
Eosinophilic esophagitis (EoE) has been reported in some individuals undergoing OIT. Symptoms may include difficulty swallowing, food getting stuck, chest pain, or abdominal discomfort. If these develop during OIT, report them to your allergist promptly — EoE associated with OIT may require dosing modifications or protocol discontinuation.
Continuing Allergen Avoidance and Carrying Epinephrine
OIT does not eliminate the need for ongoing allergen avoidance or for carrying prescribed epinephrine. Patients completing OIT continue to read labels carefully, communicate allergens when eating away from home, and carry epinephrine auto-injectors. The goal of OIT is to reduce risk from accidental exposures — not to permit deliberate consumption of the allergen beyond the prescribed maintenance dose. Stopping the maintenance dose — even temporarily due to illness or travel — should be discussed with the treating allergist, as the threshold protection can change.
- FDA — First Approved Treatment for Peanut Allergy in Children (Palforzia) (not externally verified)
- AAAAI — Allergy Conditions Library (not externally verified)
- ACAAI — Food Allergy (not externally verified)