Oral immunotherapy for food allergies can bring significant benefits to children with food allergies. It carries risks and has a significant cost. This treatment requires significant commitment from the children and their caregivers, for it to be performed safely and effectively.
by Dr Soh Jian Yi
Food allergies are common and appear to be on the rise. These allergies can be severe, and the reactions can be life-threatening. Conventional management is to ask the patient to avoid the food allergen to the best of their ability. However, accidental exposures are common. Deaths occur every year due to inadvertent exposure to a food the person is allergic to. The ongoing psychological burden on the allergic child, as well as the child’s parents – always having to be vigilant, when eating or buying food to eat every day – is considerable. Combined with greater awareness of the problems food allergies cause, there has been increased interest in the prevention and treatment of food allergies in recent years.
Oral immunotherapy for food allergies has been researched for over a decade. This treatment involves giving the allergic patient, tiny amounts of the food the patient is allergic to, to raise the “threshold of reactivity” (ToR) (the minimum amount of allergen that specific patient has to be exposed to, to develop a reaction. Exposure to amounts less than that do not cause reactions) that patient has to the food. For example, if a peanut-allergic child has the ToR raised to 20 roast peanuts’ worth, that child can eat any peanut-containing food up to 19 roast peanuts’ equivalent, without any problems. This makes it vastly safer for the child to eat (since it would be difficult to accidentally eat 20 or more roast peanuts), as well as alleviates the psychological burden on the child as well as the parents. Another benefit is to give the child more dietary choices.
The difficulty in offering this treatment lies in doing so consistently, precisely, and in amounts tiny enough that the treatment does not exceed the ToR for that patient. Many of the “high-risk” foods, such as peanut and tree nuts, tend to cause severe reactions. Patients with allergies to these high-risk foods also tend to have a very low ToR, which is why even contamination of the cooking utensil with the food allergen can result in severe allergic reactions for them.
For the above reasons, researchers have often stated that immunotherapy is not yet ready for routine clinical practice. They are right, in the sense that the degree of caution, foresight and communication between healthcare team, patient and patient’s caregivers is far greater than what would be routinely possible in many outpatient clinical practice settings.
Having said that, oral immunotherapy for food allergies in children, has been ongoing at the National University Hospital of Singapore since the year 2015. This is offered as a clinical service. Given the commitment required and stakes involved, a detailed discussion with the child and his/her caregivers is undertaken. This discussion involves costs, risks, precautions, benefits and flexible scheduling – important in our fast-paced society, since children can fall sick at any time, there are also school and overseas trips to factor in, and taking leave to bring the child to the hospital for treatment can be difficult for working parents.
The child then undergoes the treatment, which involves daily dosing at home under supervision of the adult caregiver; and visits to the children’s Day Therapy ward once or twice a month, where they will eat an increased dose of the allergen under medical supervision.
Communication with the healthcare team is available through multiple channels; the families can contact the head of the programme at any time, any day, should there be urgent or emergent issues. The need to take ownership of any concerns or upcoming scheduling plans the child or family has, and to alert the healthcare team of those concerns, is emphasized so as to ensure everything runs optimally for all involved. Likewise, the family is aware that the healthcare team takes ownership of their expertise and ability to assist, and thus will do their best to help the family – but can only do so if the family works closely with the medical team.
Near the end of the treatment, the child will be able to decide whether he/she likes the food. This is important because the treatment is not a “cure”. At the end of the treatment, the child still needs to take the food allergen regularly to maintain the higher ToR. Some children dislike the food allergen; if so, the final aim of the treatment may be to tolerate accidental ingestion, rather than meal-size amounts. This is because, if a child dislikes that food, it would not be sustainable to ask them to eat meal-size portions of that food regularly in the long term. Suppose the child undergoes peanut immunotherapy, and discovers they do not enjoy the taste of peanuts. Given the benefits of maintaining the higher ToR, it is not advisable to stop taking the peanut allergen completely, which would mean abandoning the benefits gained. Instead, to have them eat one to two peanuts regularly and for the long-term once the treatment is completed, is a small price to pay for the benefits of being much safer from accidental exposure, and the relief from the psychological burden on the child and parents.
Happily, upon completing the treatment, many children do enjoy eating the foods they were previously unable to take. Their dietary choices expand tremendously, and they are happier. Children who were unable to enjoy birthday parties fully and could not take many desserts due to egg and milk allergies, were able to do so. Some have their own birthday cakes where previously they never had one before – a joyous moment for the child and the parents.
Currently, the program is available for children with allergies to peanut, egg, milk, wheat, and tree nuts.
Dr Soh Jian Yi is a pediatrician and allergy specialist for the National University Hospital of Singapore and an assistant professor at the Yong Loo Lin School of Medicine. His research interest lies in the fields of allergy and immunology; he has a particular focus on food allergy and desensitisation. Dr. Soh runs a clinical immunotherapy program for the treatment of food allergies.