Favorable trends in the frequency of U.S. emergency department visits for food allergy, 2001-2009.

Several studies suggest an increase in both the prevalence of food allergy and in the frequency of emergency department (ED) visits for food-related allergic reactions, including anaphylaxis. This study evaluates time trends in the frequency of ED visits for food allergy, with a focus on possible differences by age. Data from two multicenter ED-based studies were used to identify the proportion of patients assigned to the International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) codes with actual food-related acute allergic reaction and the proportion of these patients with food-induced anaphylaxis. We multiplied these proportions against counts from nationally representative data (2001-2009) to estimate the number of U.S. ED visits for each ICD-9-CM code with likely food allergy. Over the 9-year study period, there were ∼1,892,000 ED visits for food allergy. The number of ED visits for food allergy did not significantly change among children aged <18 years (77,000 visits in 2001 versus 92,000 visits in 2009; p = 0.85), but among adults aged ≥18 years, there was a decline (147,000 visits versus 97,000 visits; p = 0.046). Looking across all ED visits (any cause), the proportion of ED visits for food allergy was stable for children (0.29% versus 0.28%; p = 0.22) but decreased for adults (0.18% versus 0.09%; p = 0.01). The number of U.S. ED visits for food-related acute allergic reactions is significantly higher than prior reports. These results also suggest that the frequency of ED visits for food allergy was stable or decreased from 2001 to 2009, despite reports suggesting an ongoing rise in the prevalence of food allergy.