GENERAL INFORMATION: ORAL IMMUNOTHERAPY (OIT)
What is OIT?
Oral lmmunotherapy is a procedure where a patient is given an increasing amount of allergen to eat or drink with the goal of increasing threshold for triggers. This is not a curative treatment and Epipen still needs to be carried by the patient.
How effective is OIT?
Peanut, egg and milk have been shown to desensitize 60-80% of patient’s studies. Desensitization is a state when a food allergy outcome is improved when the patient is exposed to an allergen. Desensitization requires ongoing exposure to the allergen. Sustained unresponsiveness can be achieved in 30-70% of cases but there it is likely that no permanent longstanding immunological changes occur. The younger a child is when they start OIT, the more likely they are to reach sustained unresponsiveness.
What is sustained unresponsiveness?
Sustained unresponsiveness is the state at which a patient can discontinue maintenance doses and the allergy will not return.
What is the side effects of OIT?
Most common side effects are in the gastrointestinal tract, this can be abdominal pain, vomiting, cramping. Eosinophilic Esophagitis(EoE) is a condition where allergy white cells called Eosinophils cause inflammation in the esophagus this can lead to difficulty in swallowing, vomiting, abdominal pain. EoE usually clears up if the OIT is stopped. Other side effects include wheeze, hives, itching mouth, anaphylaxis, stomach cramps, runny nose, itchy eyes.
What are the Steps?
SPECIFIC INFORMATION OIT:
Oral immunotherapy can be effective to reduce sensitivity to patients with IgE mediated food allergies. Safety is the most important factor and patients can react even after tolerating the same dose the day before. Adverse reactions can be unpredictable and unexpected that is why all factors that one can control is managed accordingly. Most adverse reactions happen during illness, exercise, or poor asthma control episodes.
- INITIAL CONSULTATION:
- Where an assessment is done and discussed. All other allergic conditions like asthma and eczema needs to be well controlled to proceed. The need for an oral food challenge is also discussed.
- A detailed history as well as clinical assessment. Risks and benefits are explained as well as any questions a patient might have. The cild is included in this discussion as often there is significant anxiety that these children suffer from and needs to be evaluated.
- Assessment Bloods
- Skin prick test inhalants
- Lung function/Peak flow
- Initial discussion of protocol
- The need for an oral food challenge will be discussed.
- INITIAL DAY ESCATATION PHASE:
- This dosing is done in the office under strict supervision of a doctor and a nurse. Vital signs will be monitored (BP, pulse, Oxygen levels in the blood, Temperature and Peak flow or lung function).
- The dosing will be done every 15-30 minutes and will stop if you or your child has significant symptoms or the desired dose it attained.
- HOME DOSING
- After initial dosing desired dose will be taken at home every day for a period of 2-4 weeks. The child must be observed for 2 hours after taking the dose.
- Doses must be delayed if you/your child has a fever, asthma flare up or viral infection. Care should be taken to not give the food allergen dose if the child has fever or is ill or has lost a tooth. No anti-inflammatory medication or exercise 2 hours after the dose.
- If the dose was delayed for more than 3 days you must return to the unit for a supervised dosing.
- Two hours after and 1 hour before the dose you are not allowed to exercise, take a long hot shower, or bath or take an anti-inflammatory or alcohol.
- BUILD UP VISITS:
- Take place every 2-4 weeks until maintenance dose is achieved. These visits will last an hour.
- You will return to the unit every 2-4 weeks to build up to a maintenance dose.
- The dose will be increased during the visit and you will need to remain in the unit for at least an hour after your dose.
- MAINTENANCE PHASE:
- Ongoing treatment with 6-12 monthly visits. Blood and skin prick tests are repeated to evaluate if allergen values are decreasing. Once your blood results values are sufficiently low a food challenge will be done to determine if sustained tolerance has been reached.
- You will take your daily dose at home as during the buildup phase. The same precautions will stay in place.
- Follow up Visits will be scheduled at Six Monthly Intervals
- FOLLOW UP TESTS:
- During the Course of the Treatment following the Bloods, Skin test as well as Lung Functions will be done at 6 Monthly Intervals.
- REFERENCES:
- Long term outcome of Peanut Oral Immunotherapy-Real Life Experience. Liat Nachson etal.
- www.aaaai.com/thecurrentstateoforalimmunotherapy(OIT)forthetreatmentoffoodallergy.
- Safety of a peanut oral immunotherapy protocol in children with peanut allergy. Alison M et-al. JACI August 2009.
- Successful oral tolerance induction in severe peanut allergy. Allergy 2009: 64 1218-1220
What are the PRO'S CON'S AND RISKS
- lf you’re familiar with the world of allergies, you are likely to have heard of someone who had immunotherapy or desensitisation to cats, dogs, grass or even BEE venom allergy. But what exactly does it entail? Let’s take a closer look to find out.
- The goal of immunotherapv is to help your immune system retains the memory of processing an allergen. ln doing so, it will continue producing the blocking antibodies preventing an allergic reaction, long after we stop the immunotherapy.
MORE ABOUT ORAL IMMUNOTHERAPY:
Oral immunotherapy (OlT) is when a trained Allergist or an allergy practitioner administers an allergic patient with incremental doses of the allergenic food. We do this to increase the patient’s threshold for triggers. Once we have reached a safe dosage, the patient will have to continue taking the same dose.
OIT is a viable option to treat peanut, tree nut, egg and milk allergies. According to medical studies, between 60% to 80% of patients have been treated effective
Although oral immunotherapy can be lifesaving and enhance a patients quality of life, we must approach it with caution. This may never be attempted without medical supervision at home or with an inexperienced practitioner. lt is also advisable to keep an Epipen at hand in the event of exposure to allergens that we did not cover in the therapy.
- ln my previous blog post, I explained the similarities and differences between immunotherapy and desensitization. But to recap: lmmunotherapy is when we deliberately expose a patient to a protein of the substance, he or she is allergic to. We tend to start at 1/100 OOOth of dosage, and then gradually escalate to a higher dose.
- Desensitization is more temporary. lt achieves a state of “tolerance”, where the body is “trained” to handle exposure to a specific allergen in the short to medium term. When a patient undergoes desensitization, the allergen must be given either for the period it is needed. For example, we can desensitize a patient who is allergic to Penicillin during an infective episode. Once we stop the incremental exposure to the allergen, the patient is likely to become allergic to it again.
WHAT ARE THE SIDE EFFECTS:
The most common side effects of OIT tends to happen in the gastrointestinal tract. Patients might experience abdominal pain, cramping or vomiting. One of the side-effects is known as Eosinophilic Esophagitis (EoE), a condition where white allergy cells called Eosinophils cause inflammation in the esophagus. This reaction can lead to difficulty in swallowing, vomiting and abdominal pain. EoE usually clears up once we stop the OlT.
Other side effects include wheezing, hives, an itchy mouth, and anaphylaxis
lf you would like to know more about oral immunotherapy and how it might be able to make a difference in your life, feel free to contact us to set up a consultation
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