In 1999, research reported in the Journal of Allergy and Clinical Immunology estimated that 1 percent of the American population is allergic to peanuts or tree nuts. For reasons that have yet to be determined, peanut and tree nut allergies are on the rise, and in December 2003, this same journal reported that the prevalence of peanut allergies doubled in the period from 1997 to 2002.

Serious food allergies cause roughly 30,000 anaphylactic reactions and 200 deaths each year in the U.S. [Sampson, H.A. (1999). Food allergy. Part 2: Diagnosis and management. Journal of Allergy and Clinical Immunology, 103(6), 981-989.]

Even with vigilance and careful management, accidental ingestions occur at an average rate of 2 per child over a median period of 5 ½ years, typically in day care settings, schools and restaurants [Sicherer, S.H., Burks, A.W., & Sampson, H.A. (1998). "Clinical features of acute allergic reactions to peanut and tree nuts in children" Pediatrics, 102(1).] Inadvertent ingestion can occur through food sharing, cross contamination of table surfaces or utensils, or misinformation regarding ingredients or food preparation.

Unlike many other food allergies, most peanut and tree nut allergic individuals have lifelong allergies with increasingly severe reactions as they get older [Sampson, H.A. (2002). Peanut allergy. New England Journal of Medicine, 346(17), 1294-1299], and frequent accidental exposure is associated with higher risk of sensitization and anaphylactic reactions.