Anaphylaxis in America: The prevalence and characteristics of anaphylaxis in the United States

Background: Although anaphylaxis is recognized as an important life-threatening condition, data are limited regarding its prevalence and characteristics in the general population. Objective: We sought to estimate the lifetime prevalence and overall characteristics of anaphylaxis. Methods: Two nationwide, cross-sectional random-digit-dial surveys were conducted. The public survey included unselected adults, whereas the patient survey captured information from household members reporting a prior reaction to medications, foods, insect stings, or latex and idiopathic reactions in the previous 10 years. In both surveys standardized questionnaires queried anaphylaxis symptoms, treatments, knowledge, and behaviors. Results: The public survey included 1,000 adults, of whom 7.7% (95% CI, 5.7% to 9.7%) reported a prior anaphylactic reaction. Using increasingly stringent criteria, we estimate that 5.1% (95% CI, 3.4% to 6.8%) and 1.6% (95% CI, 0.8% to 2.4%) had probable and very likely anaphylaxis, respectively. The patient survey included 1,059 respondents, of whom 344 reported a history of anaphylaxis. The most common triggers reported were medications (34%), foods (31%), and insect stings (20%). Forty-two percent sought treatment within 15 minutes of onset, 34% went to the hospital, 27% self-treated with antihistamines, 10% called 911, 11% self-administered epinephrine, and 6.4% received no treatment. Although most respondents with anaphylaxis reported 2 or more prior episodes (19% reporting >= 5 episodes), 52% had never received a self-injectable epinephrine prescription, and 60% did not currently have epinephrine available. Conclusions: The prevalence of anaphylaxis in the general population is at least 1.6% and probably higher. Patients do not appear adequately equipped to deal with future episodes, indicating the need for public health initiatives to improve anaphylaxis recognition and treatment.