BACKGROUND: Anaphylaxis is a potentially life-threatening systemic allergic reaction. Studies suggest that the incidence of anaphylaxis is increasing; however, recent trends in emergency department (ED) visits for anaphylaxis in the United States have not been studied. OBJECTIVE: To examine trends in the incidence and rates of anaphylaxis-related ED visits from 2005 through 2014. METHODS: We retrospectively analyzed data from a national administrative claims database including commercially insured and Medicare Advantage patients. We identified all ED visits for anaphylaxis and calculated rates as number of anaphylaxis-related ED visits per 100,000 enrollees. Rates were compared over time and by age and trigger. RESULTS: During the 10-year time period, 56,212 ED visits for anaphylaxis were identified. The median (interquartile range) age was 36 (17-52 years) years, and 58% were female. Most cases (57%) were due to unspecified triggers, 27% were associated with food, 12% were medication related, and 4% were due to insect venom. The overall rate of anaphylaxis per 100,000 enrollees increased by 101%, from 14.2 in 2005 to 28.6 in 2014 (P<.001). Rates of ED visits for anaphylaxis increased in all age groups, but the greatest increase was in children aged 5 to 17 years (196% increase; P<.001). The rate of food-related anaphylaxis increased by 124% (P<.001), and the rate of medication-related anaphylaxis increased by 212% (P<.001). CONCLUSIONS: ED visits for anaphylaxis increased between 2005 and 2014. Increases in ED visits were greatest among children. (C) 2016 American Academy of Allergy, Asthma & Immunology