Oral Immunotherapy – a glimmer of hope!
Specific Oral Immunotherapy (or “desensitisation”) to peanut has reached “market status” following the approval by the FDA of the first encapsulated peanut powder product for use in peanut densitization, in 2019. Allergist and Paediatrician Prof Claudia Gray gives her updated thoughts on this.
Food allergies are on the increase and the current cornerstone of management is strict avoidance of the allergen which the person is allergic to, coupled with well-informed emergency management after accidental ingestion. OIT, in theory, offers a glimmer of hope as more of a “cure“ for food allergy, though a more realistic goal is “raising the threshold of reactivity”- in other words requiring more of the allergen to set off an allergic response, or having a milder reaction on allergen exposure. This is a great step forward for many patients, especially those whose lives had been clouded by the anxiety of a severe allergic reaction upon trace ingestion of the allergen. Many of my patients have described OIT as “life changing.” However, the procedure is not without risk or controversy. Some of the drawbacks:
Many patients have reactions during the process, mostly mild, some severe, requiring adrenaline. There is a small risk of a more serious side effect of eosinophilic oesophagitis.
Some patients do not tolerate the procedure well at all, for example those with recurrent abdominal symptoms, and their quality of life is not actually enhanced by the procedure. Some patients fly through with no problems! A considered decision by doctor and patient needs to be taken as to whether it is worth continuing in some cases-adaptability and continued discussion are crucial.
The desensitization is real, but long-term tolerance development is still under investigation and certainly not achieved in all cases. The patient has to continue to consume the allergenic food on a regular basis after reaching a maintenance dose- prolonged dose omissions may lead to symptoms returning.
For these reasons, OIT- although now commonly used- is still not endorsed by the World Allergy Organization as a routine allergy procedure. The South African Allergy Society has not particularly commented on OIT and a few practitioners in SA are actively using it, but we need to remember that it is not the be all and end all for everyone.
We eagerly await further clinical trials – many of which look very promising – on optimal doses, duration, enhancers such as probiotics, factors improving our stats on tolerance development. In the mean time we shall continue to practice OIT with cautious optimism.
Post updated 28 May 2021