Rate of recurrent anaphylaxis and associated risk factors among Olmsted County, Minnesota, residents: A population-based study.

BACKGROUND: The rate and risk factors for recurrence of anaphylaxis are not well known. OBJECTIVE: To measure the rate and risk factors for recurrent anaphylaxis in a population-based cohort in Olmsted County, Minnesota. METHODS: We conducted a population-based cohort study using the Rochester Epidemiology Project, a comprehensive medical records linkage system, to obtain records of patients who presented to medical centers within the Olmsted County area with anaphylaxis from January 1, 2001, through December 31, 2010. We evaluated the rate and associations of risk factors with anaphylaxis recurrence. RESULTS: Among the 611 patients with anaphylaxis, 50 (8%) experienced a total of 60 recurrences within the 10-year period, resulting in a recurrence rate of 2.6 per 100 person-years. A history of atopic dermatitis (hazard ratio [HR], 5.6; 95% confidence interval [CI], 2.0-16.1; P = .001), presenting symptoms of cough (HR, 4.7; 95% CI, 2.1-10.7; P < .001) oral pruritus (HR, 9.9; 95% CI, 4.3-23.2; P < .001), and receiving corticosteroids (HR, 5.2; 95% CI, 2.3-11.7; P < .001) were associated with an increased risk of recurrence. The cardiovascular symptom of chest pain (HR, 0.24; 95% CI, 0.07-0.79; P = .02) was associated with a decreased risk of recurrence. CONCLUSION: In this epidemiologic study, the rate of recurrence was 8% during the 10-year study period (recurrence rate of 2.6 per 100 person-years). Those with atopic dermatitis and mucocutaneous or respiratory symptoms were more likely to have a recurrent anaphylactic event. Our findings underscore the importance of early patient access to self-injectable epinephrine and referral to an allergist/immunologist for additional testing and education.

Predictors of Repeat Epinephrine Administration for Emergency Department Patients with Anaphylaxis.

BACKGROUND: Risk factors that predict which patients with anaphylaxis might require repeat doses of epinephrine are poorly understood. OBJECTIVE: The objective of this study was to identify risk factors associated with the need for multiple doses of epinephrine during an anaphylactic reaction. METHODS: Patients were included if they met diagnostic criteria for anaphylaxis on presentation to the emergency department (ED) at our academic medical center between April 2008 and February 2014. Data were collected on allergic history, presenting signs and symptoms, anaphylaxis management, and disposition. Univariable and multivariable analyses were performed to estimate associations between possible risk factors and the need for multiple doses. RESULTS: Of 582 ED patients with anaphylaxis, 45 (8%) required multiple doses of epinephrine. By multivariable analysis, factors associated with the need for repeat doses were a history of anaphylaxis (odds ratio [OR], 2.5 [95% CI, 1.3-4.7]; P = .005), the presence of flushing or diaphoresis (OR, 2.4 [95% CI, 1.3-4.5]; P = .007), and the presence of dyspnea (OR, 2.2 [95% CI, 1.0-5.0]; P = .046). Patients who received more than 1 dose were more likely to be admitted to the general medical floor (OR, 2.8 [95% CI, 1.1-7.2]; P = .03) or intensive care unit (OR, 7.6 [95% CI, 3.7-15.6]; P < .001). CONCLUSION: Patients with a history of anaphylaxis, flushing or diaphoresis, or dyspnea may require multiple doses of epinephrine to treat anaphylactic reactions. Patients who require more than 1 dose are more likely to be admitted to the hospital, thus increasing health care resource utilization.