Peanut allergy is very common and affects around 2% of children in Europe. It often starts at the age of 1 to 2 years and generally persists into adulthood. Peanut ingestion triggers a variety of reactions in these patients, and a tiny quantity may suffice. These reactions, some of which can be fatal, include urticaria, breathing difficulties, gastrointestinal, ENT and cardiovascular disorders, and serious allergic reactions.

The mainstay of prevention of allergic reactions is to avoid eating anything containing peanut. Adherence to this diet is very difficult, because small amounts of peanut are present in so many foodstuffs that patients can be exposed inadvertently. Oral desensitisation is sometimes proposed, in which increasing doses of a peanut protein preparation are administered over a period of several months. However, 21% of patients who undergo desensitisation experience allergic reactions, including serious reactions, versus 7% of patients who have not been desensitised.

Two clinical trials, conducted in hospital, evaluated the efficacy of oral desensitisation with a peanut protein-based product (Palforzia°) in children aged 4 years to 17 years. This product has an unfavourable harm-benefit balance, like all the other peanut desensitisation treatments used to date. Although it reduces the incidence and intensity of allergic reactions to peanut in hospital tests, it increases the incidence of allergic reactions in everyday life, including those requiring administration of adrenaline.

In practice, oral peanut desensitisation is best avoided. It is safer for patients and their carers to focus on adhering to a peanut-avoidant diet and on learning to use adrenaline injectors correctly.

©Prescrire 1 June 2022

Source: "Peanut protein (Palforzia°) for oral desensitisation. Increased incidence of allergic reactions in everyday life" Prescrire International 2022; 31 (238): 153-156. Subscribers only.

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