Food allergies arise when the immune system reacts to harmless proteins as though they were dangerous parasites. Proteins called immunoglobulin E (IgE) antibodies, normally responsible for recognising invading parasites, become sensitive to food allergens and trigger the release of histamine, a signalling chemical that can cause symptoms ranging from hives to anaphylactic shock.
In America the share of children with food allergies rose from 3.4% in 1997 to 5.8% in 2021, with similar increases elsewhere. Food allergies carry a higher risk of anaphylaxis than other allergies, which has made treatment development slower than for pollen or dust-mite sensitivities.
A family of treatments known as immunotherapies work by repeatedly exposing the body to tiny and gradually increasing amounts of allergen. In 2020 America's Food and Drug Administration approved the first oral immunotherapy for children with peanut allergy, a powder containing peanut protein taken with food under medical supervision.
Companies are developing immunotherapies based on small fragments of allergen proteins called peptides, which appear to increase tolerance without setting off harmful immune reactions. Another avenue is blocking IgE antibodies directly. In a trial in 2024, 79 of 118 people with allergies to several foods were able to ingest 600mg of their allergens after taking a monoclonal antibody called omalizumab for 16 to 20 weeks, compared with only five of the 59 in the control group. As patients must keep taking omalizumab to feel its effects, some researchers hope to prescribe it alongside immunotherapy to build lasting tolerance.
Because the immune system becomes less flexible with age, adults are harder to treat than children and have often been excluded from trials. In April 2025 an adult-only trial showed that standard oral immunotherapy could build patients up to a dose of four daily peanuts.
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