Anaphylaxis in a Swiss university emergency department: clinical characteristics and supposed triggers.

Background: Anaphylaxis is the most severe form of acute systemic and potentially life-threatening reactions triggered by mast and basophilic cells. Recent studies show a worldwide incidence between 50 and 112 occurrences per 100,000 person-years. The most identified triggers are food, medications, and insect venoms. We aimed to analyze triggers and clinical symptoms of patients presenting to a Swiss university emergency department for adults.

Methods: Six-year retrospective analysis (01/2013 to 12/2018) of all patients (> 16 years of age) admitted with moderate or severe anaphylaxis (classification of Ring and Messmer ≥ 2) to the emergency department. Patient and clinical data were extracted from the electronic medical database of the emergency department.

Results: Of the 531 includes patients, 53.3% were female, the median age was 38 [IQR 26-51] years. The most common suspected triggers were medications (31.8%), food (25.6%), and insect stings (17.1%). Organ manifestations varied among the different suspected triggers: for medications, 90.5% of the patients had skin symptoms, followed by respiratory (62.7%), cardiovascular (44.4%) and gastrointestinal symptoms (33.7%); for food, gastrointestinal symptoms (39.7%) were more frequent than cardiovascular symptoms (36.8%) and for insect stings cardiovascular symptoms were apparent in 63.8% of the cases.

Conclusions: Average annual incidence of moderate to severe anaphylaxis during the 6-year period in subjects > 16 years of age was 10.67 per 100,000 inhabitants. Medications (antibiotics, NSAID and radiocontrast agents) were the most frequently suspected triggers. Anaphylaxis due to insect stings was more frequently than in other studies. Regarding clinical symptoms, gastrointestinal symptoms need to be better considered, especially that initial treatment with epinephrine is not delayed.