Allergology

Oral immunotherapy helps children to desensitise themselves to the foods they are allergic to by giving them small amounts of the food allergen every day and gradually building up their body's tolerance to the food.

The aim of oral immunotherapy is for the child to achieve a maintenance dose of the allergen and to take it regularly for at least 3 years, with the aim of preventing a severe allergic reaction in the event of accidental exposure or cross-contamination. For a certain proportion of children, the food can also become part of the diet again.

First, the tolerance threshold is defined in an oral provocation test, i.e. an allergic reaction occurs: this can be felt by the patient alone, e.g. itching in the mouth, or objectified by the doctor or nurse, e.g. urticaria, vomiting, shortness of breath.

This provocation test takes place at the UKBB day clinic. In most cases, oral immunotherapy is then started the following day, with a dose that is lower than the dose that produced a reaction. If more than 2 weeks have passed since the provocation test, the first dose should be taken again in hospital. If well tolerated, this dose will be taken daily.

Another possibility is the so-called Ultrarush method, where small amounts of proteins are administered at regular intervals, which alone cause a subclinical allergic reaction; i.e. without the patient experiencing a strong allergic reaction, sometimes there may be a few wheals, or an itchy throat, or even a slightly blocked nose. The aim here is to regularly increase the tolerance threshold until around 6-10mg of the protein is tolerated. This phase lasts 1 day and also takes place at the UKBB day clinic.

With good tolerance, the dose is increased every 2-4 weeks. Consumption is generally well tolerated, usually with minor side effects (throat itching, abdominal pain) that do not require therapy. Adrenaline is required in less than 1% of doses given (1x in approximately 10-20% of patients, data for peanut). The dose increase (25-30% increase, depending on tolerance) also takes place during a short provocation test: The following dose is consumed in the hospital and is followed by one hour of monitoring.

The duration of this dose increase phase varies from child to child and depends on the family's expectations (e.g. the child should be able to eat peanuts without problems, traces should be tolerated, no more risk of accidents), the dose achieved in the provocation test and the side effects during the build-up phase. This goal is defined together with the family.

Sometimes immunotherapies are carried out for several foods at the same time, so a lower dose can sometimes be advantageous, as otherwise the quantities become too large, especially for younger children. This build-up phase is followed by a maintenance phase (daily consumption of the maximum amount) of about 1 month. After that, the food should be taken 3 times a week for at least 3 years.

It is known that the success of a therapy increases with the frequency with which it is taken, i.e. the more frequently it is taken, the more likely it is that the food can actually form part of the diet. This is less often the case with older children. The specific IgE should be measured every 6 months and a new provocation test can be carried out to define the new tolerance threshold.

During the oral challenge test, patients will show a hypersensitivity reaction, e.g. redness, a feeling of heat, itching, wheals, swelling around the lips, eyes or tongue, rarely also severe symptoms such as shortness of breath, dizziness, diarrhoea, a drop in blood pressure or a shock reaction. The test is cancelled as soon as the first typical and clear allergic reactions occur. Appropriate emergency treatment is then initiated immediately.

Hypersensitivity reactions occurring later (i.e. after discharge) are very rare. Patients are provided with an emergency medication kit which should be administered in the event of such reactions. Medical assistance should then be sought immediately, especially if adrenaline is administered.

During immunotherapy, there may be frequent side effects, i.e. allergic reactions, depending on the food.

Physical activity or warm baths should be avoided for 2 hours after the dose has been taken. Please choose a time to take the daily dose that allows you or a trusted person (who can recognise and manage an allergic reaction) to monitor your child for 1 hour.

During feverish infections and/or when taking antipyretic medication, such as paracetamol and ibuprofen, a break should be taken. If necessary, antihistamines can be taken about 30 minutes before the dose taken in the case of enoral pruritus.

If the portions cannot be taken over a longer period of time, e.g. in the case of infections, the dose must be reduced in certain cases. If your child has not taken the portions, you should contact the allergy team immediately to decide how to proceed with the therapy.