Anaphylaxis in Victoria: presentations to emergency departments, with a focus on drug- and antimicrobial-related cases

Objective: To investigate the causes, characteristics, and outcomes of anaphylaxis, particularly drug-related anaphylaxis, in Victoria during the first two years of mandatory notification. Design: Review of all anaphylaxis cases reported by emergency departments to the Victorian Department of Health and Human Services. Setting, participants: People presenting to all public and private hospital emergency departments in Victoria, 1 November 2018 -31 December 2020. Main outcome measures: Rates of drug-and food-related anaphylaxis, by age group; characteristics of cases of drug-related anaphylaxis. Results: A total of 4273 anaphylaxis episodes were reported (females: 2292 cases, 54%); the overall anaphylaxis rate was 31.9 episodes per 100 000 person-years. The most frequently reported causes were foods (2659 cases, 62%); drugs were implicated in 533 cases (12%), insect venoms in 342 (8%), and other causes in 144 (4%). No deaths were recorded. The median age in cases of food-related anaphylaxis was 17 years (IQR, 6-29 years), and 45 years (IQR, 30-60 years) in cases of drug-related anaphylaxis. Hospitalisation was required by 1538 patients (36%) and intensive care by 111 ( 2.6%; 7% of people admitted to hospital). Antimicrobial drugs were implicated in 258 cases of drug-related anaphylaxis (48%) and non-steroidal anti-inflammatory drugs in 85 cases (16%). Penicillin-class agents were implicated in 143 cases of antimicrobial-related anaphylaxis (56%), cephalosporins in 80 cases (31%). Conclusion: Our review of notified cases of anaphylaxis in Victoria over two years provides insights into drug-and antimicrobial-related anaphylaxis in non- -hospitalised people presenting to emergency departments.