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

Abstract

Anaphylaxis is an acute, potentially life-threatening condition caused by IgE-mediated mast cell degranulation. The estimated lifetime prevalence of all-cause anaphylaxis in the United States is about 2%, 1,2 with an estimated incidence of about 30 episodes per 100 000 person-years. 3 The prevalence of anaphylaxis appears to be increasing, 2,4 particularly among children. 5 Estimating rates of drug-related anaphylaxis is difficult, partly because of classification problems. 6 Food allergy is the most frequent trigger of anaphylaxis during childhood, while drugrelated anaphylaxis increases with age, and is responsible for about 40% of all cases in the United States and the United Kingdom. 2,7 From 1 November 2018, the Victorian Department of Health and Human Services listed anaphylaxis as a notifiable condition. 8 The incidence, causes, and characteristics of anaphylaxis in a large Australian state could now be analysed for the first time. The aim of our analysis of data from the first two years of mandatory reporting was to determine the incidence of anaphylaxis reported from emergency departments in Victoria, particularly drug-related anaphylaxis. We also examined clinical outcomes following anaphylaxis, including differences in presentation and outcome by drug class and antimicrobial agent sub-class. MethodsWe reviewed all cases of anaphylaxis reported to the Victorian Department of Health (previously: Victorian Department of Health and Human Services) during 1 November 2018 -31 December 2020. The Department collects demographic and outcomes data in a structured case report form for all cases of anaphylaxis in people presenting to Victorian public or private hospital emergency departments. 8 Other cases of anaphylaxis, including episodes in hospitalised patients, are not notifiable.The Department provided summary epidemiological data (counts, median age, outcomes) for all reported cases of anaphylaxis during 1 November 2018 -31 December 2020. De-identified, case-level data for all cases of drug-related anaphylaxis were also requested and provided, including patient age, sex, requirement for inpatient or intensive care unit admission, whether the case was one of first-time anaphylaxis, death from anaphylaxis, and drug name and type. We analysed drug-related anaphylaxis by class (eg, antimicrobial) and subclass (eg, cephalosporins).Data quality was checked by epidemiologists at the Department of Health, and assessed for labelling consistency by author GPD. Data are routinely cleaned on receipt of notifications in order to correct misclassified causes, other obvious errors, and duplicate notifications. Further, Department of Health epidemiologists periodically audit the collated data for accuracy.

Contemporary trends in anaphylaxis burden and healthcare utilisation in Western Australia: A linked data study

“…Population-based studies from Australia, Asia, the United States, Europe, and the United Kingdom across similar time frames, indicate rates for total anaphylaxis of between 4 and 76 per 100 000 person-years. 10 , 11 , 14 , 15 , 16 , 17 These are mostly based on inpatient and emergency data. Inherent issues with the collection and interpretation of anaphylaxis data means that making any direct comparisons between populations is open to misinterpretation.…”

“…Even so, when comparing published rates from around the world using single health datasets, we still found higher rates in WA than elsewhere. 11 , 14 , 17 , 18 It is hard to determine if disease burden is actually higher in the WA population or whether there are important differences in diagnosis, management, or health seeking behaviour. Even within the state, there are differences in health care access across regions.…”

Drug‐induced anaphylaxis in Australia: we need a national drug allergy registry

“…Just over two years ago, the Victorian Department of Health introduced mandatory reporting of cases of anaphylaxis in people presenting to public and private emergency departments, 1 facilitating data collection unique in Australia. In this issue of the MJA , Drewett and colleagues report their analysis of the first two years of data collected, focusing on medication‐related anaphylaxis 2 . While food allergy was the leading cause of anaphylaxis, especially in younger people, drug‐related anaphylaxis accounted for 12% of all cases, and for a relatively high proportion in adults aged 40 years or more.…”

“…While food allergy was the leading cause of anaphylaxis, especially in younger people, drug‐related anaphylaxis accounted for 12% of all cases, and for a relatively high proportion in adults aged 40 years or more. Antimicrobial agents and non‐steroidal anti‐inflammatory drugs were most frequently involved 2 …”

“…Immediate (IgE‐mediated) drug allergy can lead to life‐threatening anaphylaxis. While drug allergies are the most frequent causes of fatal anaphylaxis in Australia, 3,4 no drug‐related anaphylaxis deaths were recorded in the Victorian data 2 . Not all life‐threatening adverse drug reactions (ADRs) are immediate.…”