Emergency Management of Food Allergy: Systems Perspective
Purpose of Review: Food-related allergic reactions are the leading cause of anaphylactic reactions treated in the emergency department, accounting for approximately 30 000 emergency department visits each year, and 150-200 deaths. The purpose of this review is to examine current research on food-related allergic reactions in the emergency department, and to provide suggestions for how to improve emergency department management.
Recent Findings: There are few published studies since March 2003 that examine the emergency management of food-related allergic reactions. Earlier studies found that few patients treated in the emergency department for this problem received health education (e.g., instructions to avoid offending food allergens), a prescription for self-injectable epinephrine, or referral to an allergy specialist at emergency department discharge. A recent multicenter study by our research group demonstrated that emergency department patients with food-related allergic reactions continue to receive care discordant from guidelines for the emergency management of allergic disorders and anaphylaxis. Discordance is low even among those with multisystem complaints consistent with anaphylaxis.
Summary: Concordance with suggested guidelines for the treatment of severe acute allergic reactions remains poor. Development of a simple, clinical definition of food-related anaphylaxis is needed to improve emergency management. Dissemination of guidelines for the emergency management of anaphylaxis, and creation of systems to implement these guidelines, are essential for the improved treatment of food-related allergic reaction and anaphylaxis in the emergency department.

The prevalence of anaphylaxis in Westernized countries has been difficult to determine. A review article by Neugut and colleagues estimates the US prevalence of anaphylaxis to be anywhere between 1 and 15%. By contrast, a population-based study in Olmsted County, Minnesota, by Yocum and colleagues concluded that the prevalence of anaphylaxis was less than 1%. A review of recent literature from the USA, Canada, and the UK yields prevalence estimates ranging from 0.3-0.6 to 0.95%.

Estimates of the burden of specific types of anaphylaxis, such as food-related anaphylaxis, also vary. Yocum and colleagues, investigating the epidemiology of anaphylaxis among residents in Olmstead County, Minnesota, found 30 anaphylaxis events per 10 000 person-years (95% confidence interval 25-35 events); 36% of incident anaphylactic events were attributed to ingestants. Sicherer et al . conducted a nationwide, random-digit-dial telephone survey and found a prevalence of self-reported peanut and tree nut allergies of 1.1%; only 24% of cases who had seen a physician for their allergy reported receiving a prescription for self-injectable epinephrine.

While estimates of the prevalence of anaphylaxis vary, and most estimates indicate that perhaps 1% are affected, the condition is not rare. Even 1% of a large number (e.g. the US population of 290 million) yields a large number of affected individuals (2.9 million). Nevertheless, and despite the life-threatening nature of anaphylactic reactions, little is known about the burden of anaphylaxis in the emergency department. Among recent studies, the prevalence of anaphylaxis among all emergency departments is estimated to be less than 1%. More recently, food-related anaphylaxis has been cited to be the leading cause of anaphylactic reactions treated in the emergency department. Estimates suggest that there are approximately 30 000 food-related anaphylactic reactions treated in the emergency department annually in the USA. These estimates also suggest that there are approximately 2000 hospitalizations and 150-200 deaths each year. Foods responsible for most severe reactions include peanuts, tree nuts, fish, and shellfish. Timely and appropriate treatment is necessary to prevent progression of reactions. Individuals with a history of anaphylaxis are at an increased risk of a subsequent episode.

Additionally, guidelines recommend treatment of all severe allergic and anaphylactic reactions with epinephrine, teaching of proper techniques for self-injectable epinephrine, and referral to an allergist. A prompt and accurate diagnosis to identify those at greatest risk for adverse outcomes is essential for effective emergency management. Given such large variability in anaphylaxis estimates in the general population - and in the emergency department - and reports suggesting that the prevalence of allergies is rising, more work is needed develop clinical definitions that would allow for better measurement of the actual prevalence of food-related allergic reaction and anaphylaxis, and promote improved management of these problems in the emergency department.

This article reviews the sparse literature, to date, on the management of food-related allergy and anaphylaxis in the emergency department. Additionally, we suggest steps that can be taken to improve the identification and management of this condition in the emergency department setting.