Increase in anaphylaxis-related hospitalizations but no increase in fatalities: An analysis of United Kingdom national anaphylaxis data, 1992-2012

Fatal anaphylactic reactions to foods are continuing to occur, and better characterization might lead to better prevention. The objective of this report is to document the ongoing deaths and characterize these fatalities. We analyzed 32 fatal cases reported to a national registry, which was established by the American Academy of Allergy, Asthma, and Immunology, with the assistance of the Food Allergy and Anaphylaxis Network, and for which adequate data could be collected. Data were collected from multiple sources including a structured questionnaire, which was used to determine the cause of death and associated factors. The 32 individuals could be divided into 2 groups. Group 1 had sufficient data to identify peanut as the responsible food in 14 (67%) and tree nuts in 7 (33%) of cases. In group 2 subjects, 6 (55%) of the fatalities were probably due to peanut, 3 (27%) to tree nuts, and the other 2 cases were probably due to milk and fish (1 [9%] each). The sexes were equally affected; most victims were adolescents or young adults, and all but 1 subject were known to have food allergy before the fatal event. In those subjects for whom data were available, all but 1 was known to have asthma, and most of these individuals did not have epinephrine available at the time of their fatal reaction. Fatalities due to ingestion of allergenic foods in susceptible individuals remain a major health problem. In this series, peanuts and tree nuts accounted for more than 90% of the fatalities. Improved education of the profession, allergic individuals, and the public will be necessary to stop these tragedies.

The unpredictability of anaphylactic reactions and the need for immediate, often improvised treatment will make controlled trials impracticable; other means must therefore be used to determine optimal management. This study aimed to investigate the circumstances leading to fatal anaphylaxis. A register was established including all fatal anaphylactic reactions in the UK since 1992 that could be traced from the certified cause of death. Data obtained from other sources suggested that deaths certified as due to anaphylaxis underestimate the true incidence. Details of the previous medical history, the reaction and necropsy were sought for all cases. Approximately half the 20 fatal reactions recorded each year in the UK were iatrogenic, and a quarter each due to food or insect venom. All fatal reactions thought to have been due to food caused difficulty breathing that in 86% led to respiratory arrest; shock was more common in iatrogenic and venom reactions. The median time to respiratory or cardiac arrest was 30 min for foods, 15 min for venom and 5 min for iatrogenic reactions. Twenty-eight per cent of fatal cases were resuscitated but died 3 h-30 days later, mostly from hypoxic brain damage. Adrenaline (epinephrine) was used in treatment of 62% of fatal reactions but before arrest in only 14%. Immediate recognition of anaphylaxis, early use of adrenaline, inhaled beta agonists and other measures are crucial for successful treatment. Nevertheless, a few reactions will be fatal whatever treatment is given; optimal management of anaphylaxis is therefore avoidance of the cause whenever this is possible. Predictable cross-reactivity between the cause of the fatal reaction and that of previous reactions had been overlooked. Adrenaline overdose caused at least three deaths and must be avoided. Kit for self-treatment had proved unhelpful for a variety of reasons; its success depends on selection of appropriate medication, ease of use and good training.

Detailed data on fatal anaphylaxis are limited, with national anaphylaxis fatality data for the United Kingdom and food-induced anaphylaxis fatality data for the United States. Time trends for anaphylaxis fatalities are not available. We examined causes, demographics, and time trends for anaphylaxis fatalities in Australia between January 1997 and December 2005 and compared these with findings for anaphylaxis admissions. Data on anaphylaxis deaths and hospital admissions were extracted from a national database. Death certificate codes were analyzed to determine the likely cause and associated comorbidities. There were 112 anaphylaxis fatalities in Australia over 9 years. Causes were as follows: food, 7 (6%); drugs, 22 (20%); probable drugs, 42 (38%); insect stings, 20 (18%); undetermined, 15 (13%); and other, 6 (5%). All food-induced anaphylaxis fatalities occurred between 8 and 35 years of age with female preponderance, despite the majority of food-induced anaphylaxis admissions occurring in children less than 5 years of age. Most insect sting-induced anaphylaxis deaths occurred between 35 and 84 years almost exclusively in male subjects, although bee sting-induced admissions peak between 5 and 9 years of age with a male/female ratio of 2.7. However, most drug-induced anaphylaxis deaths occurred between 55 and 85 years with equal sex distribution similar to drug-induced anaphylaxis admissions. There was no evidence of an increase in death rates for food-induced anaphylaxis, despite food-induced anaphylaxis admissions increasing approximately 350%. In contrast, drug-induced anaphylaxis deaths increased approximately 300% compared with an approximately 150% increase in drug-induced anaphylaxis admissions. The demographics for anaphylaxis deaths are different to those for anaphylaxis presentations. Anaphylaxis mortality rates remain low and stable, despite increasing anaphylaxis prevalence, with the exception of drug-induced anaphylaxis deaths, which have increased.