Over the last two decades, the prevalence of peanut and tree nut allergy has increased throughout the western world. Adverse reactions to these foods account for over 50% of all deaths resulting from food-related anaphylaxis. Until recently, evidence suggested that all peanut and tree nut allergy were permanent. It is now known that about 20% and 10%, respectively, of young patients outgrow peanut and tree nut allergies. Achieving tolerance is associated with increasing circulating T regulatory cells and reduced production of allergen-specific IgE. Reliable predictors of resolution are not yet available. A direct correlation between skin test weal size and allergen-specific IgE, at the time of diagnosis and likelihood of resolution, has been reported. Resolution of peanut or tree nut allergy cannot be determined conclusively by either allergen-specific IgE analysis or by skin prick testing. Oral food challenge is the gold standard for determining resolution of food allergy. Food challenges should only be undertaken in a clinical setting fully equipped to deal with a potential severe adverse reaction. Approximately 8% of patients who outgrow peanut allergy may suffer a recurrence, but recurrent tree nut allergy has not been reported to date. Infrequent ingestion of peanut may be related to the re-emergence of allergy. Induction of tolerance through oral immunotherapy or sublingual immunotherapy is now being actively studied, but remains experimental. Studies have reported short-term desensitization to peanut, but ongoing follow-up will determine whether tolerance is achieved long term.
Cite this as: A. M. Byrne, J. Malka-Rais, A. W. Burks and D. M. Fleischer, Clinical & Experimental Allergy, 2010 (40) 1303–1311.