SOS Allergo · I understand & manage
Food oral immunotherapy
Also called oral immunotherapy: gradually increasing the reaction threshold
Food oral immunotherapy involves regularly giving a precisely defined amount of the food to which the person is allergic. Its main goal is to gradually increase the amount needed to trigger a reaction and provide better protection against accidental exposure.
In this sheet
3 essential points
Desensitisation ≠ cure
During OIT, the reaction threshold may increase. This protection often depends on continuing treatment regularly; whether it persists after treatment is stopped is much less certain.
The daily dose is a treatment
The amount, preparation, schedule and adjustments are defined by the team. Do not increase the dose yourself, double a missed dose or restart on your own after a prolonged interruption.
Adrenaline remains necessary when prescribed
OIT does not immediately remove the risk of a reaction. The action plan and auto-injector remain essential when indicated.
What is the goal of OIT?
| Before OIT | Goal of OIT |
|---|---|
| A small amount can trigger a reaction | Increase the reaction threshold |
| Risk during accidental ingestion | Reduce this risk |
| Major anxiety about errors or contamination | Provide a larger safety margin |
| Food avoidance | Depending on the goal, sometimes allow controlled ingestion over time |
For which foods?
- Peanut: this is currently the food with the strongest evidence in children and teenagers.
- Cow’s milk and egg: OIT may be offered for some persistent allergies, often after age 4.
- Tree nuts, sesame and other foods: protocols are available in some specialist centres, with less consistent evidence.
Who may benefit from OIT?
Before offering treatment, the team checks the diagnosis of IgE-mediated allergy, reaction history, age and natural history of the allergy, asthma and its control, digestive symptoms, treatments and the ability to follow the protocol every day.
How does treatment proceed?
| Stage | What happens |
|---|---|
| 1. Starting treatment | The first doses or major increases are given under supervision according to the centre’s protocol. |
| 2. Gradual dose increases | The amount of food is increased in stages. Several appointments may be needed. |
| 3. Maintenance | Once the target dose is reached, it is taken regularly at home according to the team’s instructions. |
For how long?
OIT is a long-term treatment. There is no single duration for every patient and every food. The maintenance dose may be continued for several years, sometimes adjusted and then reassessed.
Everyday rules
Why can a usually tolerated dose cause a reaction?
Some cofactors may alter the reaction threshold. The exact rules depend on the centre’s protocol.
| Situation | What to do |
|---|---|
| Feeling well | Usual dose according to the protocol. |
| Fever / infection | Follow the team’s instructions before taking the dose. |
| Asthma unusually troublesome | Do not dismiss it; follow the protocol and contact the team if needed. |
| Vomiting / digestive illness | Follow the centre’s instructions. |
| Planned physical exercise | Observe the interval specified by the team. |
| Missed dose | Never double it on your own. |
| Several interrupted doses | Ask how to restart. |
| Reaction to a previously tolerated dose | Follow the action plan and inform the team. |
What reactions may occur?
Most reactions reported during OIT are mild or moderate, but more significant reactions are possible.
| Possible symptoms | Examples |
|---|---|
| Mouth / throat | Tingling, itching |
| Skin | Redness, urticaria |
| Digestive system | Abdominal pain, nausea, vomiting |
| Respiratory system | Cough, wheezing, breathing difficulty |
| Systemic reaction | Possible anaphylaxis |
If a significant reaction occurs after a dose
Follow your emergency plan immediately and use adrenaline if the criteria in your plan are met. Then inform the OIT team before changing or restarting doses.
Which digestive symptoms should be reported?
Inform the team about persistent or repeated symptoms: abdominal pain, vomiting, marked nausea, difficulty swallowing, a feeling that food is getting stuck or unusual food refusal.
Eosinophilic oesophagitis (EoE) may rarely develop or become apparent during oral immunotherapy. This is unusual but important enough to report persistent digestive symptoms.
What about asthma?
Poorly controlled asthma increases risk during an allergic reaction. Maintenance treatment, adherence, symptoms, bronchodilator use and exacerbations must therefore be monitored during OIT.
Must I always carry my adrenaline auto-injector?
Yes, when it has been prescribed. OIT does not remove the need for an adrenaline auto-injector, action plan or knowing how to recognise and treat anaphylaxis.
OIT and OFC are not the same
| OFC | OIT |
|---|---|
| Oral food challenge | Tolerance induction / oral immunotherapy |
| Diagnostic test | Treatment |
| Performed on one occasion | Continued over time |
| Increasing doses to determine the reaction | Repeated doses to increase the reaction threshold |
| Under medical supervision | Supervised start/increases followed by maintenance, usually at home |
Effectiveness, quality of life and limitations
OIT can increase the reaction threshold and reduce fear of accidental exposure. However, it requires regular dosing, daily organisation, appointments and management of cofactors. Its effect on quality of life varies between patients and across treatment stages.
Does OIT work for everyone?
- Good desensitisation in some patients.
- Partial desensitisation in others.
- Adverse effects that may prevent the planned dose from being reached.
- Treatment may need to be stopped.
- Some protection may be lost when doses are interrupted.
What if OIT is not suitable?
Standard management remains entirely valid: targeted avoidance, an action plan, education, adrenaline when indicated and allergy follow-up. Other immunomodulatory approaches may be discussed in some specialist settings.
Common misconceptions
| Misconception | SOS Allergo guidance |
|---|---|
| ‘OIT cures my allergy.’ | Not necessarily: its primary goal is desensitisation. |
| ‘Target dose reached = treatment finished.’ | No: a maintenance phase is generally required. |
| ‘I can eat the food freely.’ | Not without the team’s explicit approval. |
| ‘If I miss a dose, I double it tomorrow.’ | No. |
| ‘A dose tolerated 100 times can no longer cause a reaction.’ | False: illness, exercise, asthma or other cofactors may alter the threshold. |
| ‘OIT replaces my adrenaline auto-injector.’ | No. |
| ‘An oral food challenge and OIT are the same thing.’ | No: one is a test, the other a treatment. |
Before starting: questions to ask
- What is my goal: protection from accidental exposure or eating the food?
- What will my target dose be and how often must I take it?
- What should I do if I have a fever, before/after exercise or if I miss a dose?
- When should I temporarily withhold a dose and whom should I call if I react?
- How long is treatment planned and when will it be reassessed?
Final message
Food oral immunotherapy is not simply ‘eating a little of the allergenic food’. It is a genuine treatment, built up gradually and monitored by a specialist team. Success depends on the medical protocol, regular dosing, asthma control, management of cofactors and a clear understanding of the emergency plan.
Download the validated sheet (PDF in French)
Find all the guidance and tables in the validated patient document (in French).
You may also want to read
Main references
- Santos AF, et al. EAACI guidelines on the management of IgE-mediated food allergy. Allergy. 2025;80:14-36.
- Pajno GB, et al. EAACI Guidelines on allergen immunotherapy: IgE-mediated food allergy. Allergy. 2018;73:799-815.
- Rosser S, et al. Systematic Review and Meta-Analysis of Oral Immunotherapy Effect on Food Allergy-Related Quality of Life. Allergy. 2025.
- EAACI Task Force. Systematic review and meta-analysis on confirmed eosinophilic esophagitis as a side effect of allergen immunotherapy.
General information: This sheet provides general guidance. It does not replace your centre’s protocol, your emergency plan or your team’s personalised instructions.
Scientific review: September 2026 · sosallergo.fr