Pediatric Anaphylaxis in the Prehospital Setting: Incidence, Characteristics, and Management

Although hospital presentations for pediatric anaphylaxis have been described in the literature, a minimal amount is known regarding the incidence, characteristics, and management of pediatric anaphylaxis presenting to emergency medical services (EMS).

We performed a retrospective observational study of pediatrics (≤16 years) presenting to EMS in Victoria, Australia. Patients with suspected anaphylaxis were included if they were treated with epinephrine before or after EMS arrival. We used descriptive statistics to compare baseline characteristics and linear regression to assess trends in incidence over time.

Between July 2008 and June 2016, we identified 2,137 pediatric anaphylaxis presentations. Overall, 59% were male and 70% had pre-existing anaphylaxis. The age-adjusted incidence increased over the study period, from 11.8 presentations per 100,000 person-years in 2008-09 to 38.7 in 2015-16 (p for trend < 0.001). Common suspected allergens included nuts (52%) and dairy/milk formula (17%). In total, 1,333 (62%) patients received epinephrine via an autoinjector, and 51 (2%) from a doctor before EMS arrival. When compared to patients receiving epinephrine after EMS arrival, patients treated prior were more likely to present with vital signs within normal limits, including heart rate (66% vs. 84%, p < 0.001), systolic blood pressure (77% vs. 93%, p < 0.001) and respiratory rate (79% vs. 91%, p < 0.001). The most common EMS interventions were intramuscular epinephrine (45%) and inhaled salbutamol (14%). Three out-of-hospital cardiac arrests were observed, two of whom received endotracheal intubation.

The incidence of prehospital pediatric anaphylaxis is increasing significantly. Despite this, most patients are hemodynamically stable on presentation and few require emergency treatments beyond the administration of intramuscular epinephrine.