Increasing Allergy-Related Emergency Department Visits in the United States, 2007 to 2015

Background: Allergic reactions, angioedema, and anaphylaxis are commonly treated in the emergency department (ED). Contemporary evidence suggests that these conditions may be increasing in the United States. Objective: To evaluate the contemporary epidemiology and trends of ED visits for allergic reactions, angioedema, and anaphylaxis in the United States from 2007 to 2015. Methods: Using de-identified data from the National Hospital Ambulatory Medical Care Survey from 2007 to 2015, we identified cases of acute allergic reactions, angioedema, and anaphylaxis through International Classification of Diseases, 9th Revision, Clinical Modification codes and conducted a retrospective analysis of rates and trends of these allergy-related ED visits. Results: There was a 14% overall increase in allergy-related ED visits between 2007 and 2015. Approximately 10 million ED visits in this time frame were associated with allergy-related conditions accounting for 0.85% (95% CI, 0.79-0.90) of all ED visits in the United States. Almost 3% of allergy-related ED visits were coded as anaphylaxis of which 46.1% (95% CI, 27.5-64.6) received epinephrine. Patients younger than 10 years had a higher relative risk (1.3; 95% CI, 1.0-1.6; P =.027) of allergy-related ED visits per 1000 ED visits than patients 65 years and older, and women also had a higher relative risk (1.4; 95% CI, 1.2-1.5; P <.001) than men. Conclusions: Allergy-related ED visits increased 14% from 2007 to 2015, with the highest relative risk occurring in patients younger than 10 years. These data provide further evidence of increasing allergic conditions in the United States.