Introduction

Food allergy is a serious and potentially life-threatening health issue that appears to be increasing in the United States.^1-3 Indeed, food is the major cause of anaphylaxis in the United States,⁴ and food allergies are believed to account for 150 deaths per year.^5,6

Although the exact incidence is unknown, anaphylaxis may affect up to 2% of the population.7 Further, the annual incidence of anaphylaxis appears to be increasing in the United States, particularly among younger individuals.²

Given the potentially fatal consequences of anaphylaxis related to food allergy, health care professionals must be able not only to recognize and treat anaphylaxis promptly, but also to educate their patients on how to manage this life-threatening condition.

In order to assist health care professionals in making appropriate decisions regarding the diagnosis and management of food allergy, the National Institute of Allergy and Infectious Diseases (NIAID), working with more than 30 professional organizations, federal agencies, and patient advocacy groups, has developed clinical practice guidelines for the diagnosis and management of food allergy.¹ These guidelines were approved by ACEP, which had representation on the project’s coordinating committee.

The Growing Problem

Although difficult to compare due to difference in study design, recent epidemiologic studies suggest that the prevalence of food allergy has increased over the past 10-20 years.^1-3 Recent data indicate the prevalence of food allergy is 8.0% among children in the United States, a number greater than that previously reported.³ Among these children with food allergies, 38.7% had a history of severe reactions and 30.4% had multiple food allergies.³

Health care utilization associated with food allergy in the United States is considerable. Ambulatory care visits for food allergy in this country nearly tripled among children younger than 18 years of age between 1993 and 2006,² while hospitalizations among this group increased from an average of 2,600 discharges per year in 1998-2000 to 9,500 in 2004-2006.2 Further, extrapolation of data from the National Electronic Injury Surveillance System (NEISS) predicted that food-related allergic symptoms accounted for more than 20,000 hospital emergency department visits in the United States during a two-month period.⁸

Despite potentially fatal consequences, anaphylaxis due to food allergy is often underrecognized and/or undertreated. A recent review of food-allergic events from the NEISS indicated that 57% of likely anaphylactic events did not have an emergency department diagnosis of anaphylaxis according to standard criteria.⁸ Further, delay in the administration of epinephrine has been noted to contribute to fatalities associated with food related anaphylaxis.^5,9-12

Characterizing Food Allergy

A food allergy is defined as an adverse health effect arising from a specific immune response that occurs reproducibly on exposure to a given food.1 Food allergens are those specific components of food or ingredients within food (typically glycoproteins) that elicit specific immune reactions.1 Although some allergens cause allergic reactions primarily if eaten raw, most food allergens can still elicit reactions even after they have been cooked or even digested.1 Cross-reactivity among food allergens is common, frequently occurring among different shellfish and among tree nuts.¹

More than 170 foods have been reported to cause IgE-mediated reactions.¹ More than 90% of allergic reactions in affected individuals involve eight types of foods: peanuts, tree nuts, fish, shellfish, cow’s milk, soy, eggs, and wheat.13 Although many children will eventually tolerate milk, egg, soy, and wheat, far fewer will outgrow true allergies to tree nuts and peanuts.¹

The symptoms of food allergy are variable and can affect multiple organ systems.¹ The onset of symptoms varies from a few seconds or minutes after contact with the allergen to several hours,¹⁴ but the majority of events occur within 2 hours of exposure.15 A pattern of biphasic anaphylaxis has also been described in which symptoms recur after the apparent resolution of the initial episode.^16,17 Unfortunately, the severity of allergic reactions to food cannot be accurately predicted by the severity of previous reactions, allergen-specific IgE levels, or the size of the wheal from skin prick tests.1 Coexistent asthma is the most commonly identified factor associated with the most severe allergic reactions to foods.¹ Indeed, children with coexisting food allergy and asthma may be more likely to experience anaphylactic reactions and be at higher risk of death.^11,13

Children who have a coexisting food allergy as well as asthma may be more likely to experience anaphylactic reactions and be at a higher risk of death.

Managing Anaphylaxis

Prompt recognition and management of the signs and symptoms of anaphylaxis are essential to managing it.¹⁶ Immediate interventions for patients experiencing anaphylaxis include assessment of airway and breathing, circulation, and level of consciousness; administration of intramuscular (IM) epinephrine; and placement of the patient in a supine position in order to slow the progression of hemodynamic compromise.¹⁶ IM epinephrine injection is first-line treatment in all cases of anaphylaxis,1,16,18 and along with the use of oxygen, is considered the most important therapeutic agent administered for anaphylaxis.¹⁶

The appropriate dose of IM epinephrine should be administered immediately at the onset of symptoms, even if the diagnosis is uncertain.^16,18 At a concentration of 1:1000, the recommended dose of epinephrine via auto-injector is 0.15 mg for patients weighing 10-25 kg and 0.3 mg for patients weighing > 25 kg.¹

Epinephrine may be administered every 5 to 15 minutes as necessary, and if symptoms progress or recur (ie, biphasic reaction), repeat epinephrine dosing is recommended over adjunctive treatments.^1,16

Although up to a third of patients require more than one dose,19 additional measures (eg, intravenous epine- phrine, volume replacement, vasopressors) may be needed in patients not responding to multiple doses.¹⁶

Supportive care with nebulized therapy, vasopressors, antihistamines, or corticosteroids may be beneficial for specific symptoms, but these are not replacements for epinephrine and should be administered only after epinephrine.¹⁶ Patients should be observed after acute treatment to monitor for biphasic reactions or possible recurrence as the epinephrine wears off.¹⁸ Because initial clinical presentation cannot reliably predict biphasic or protracted anaphylaxis, observation periods must be individualized.¹⁶

Conclusion

With the growing population of persons with food allergies in the United States, education of medical staff, patients, and their caregivers is critically important. Avoidance of specific food allergens is recommended, and individuals with food allergy and their caregivers should be taught how to interpret ingredient lists on food labels.¹ In addition, all patients who have experienced anaphylaxis should be given a prescription for two epinephrine auto-injectors and instructed on proper self-administration.^16,18 Patients should be counseled to store epinephrine auto-injectors properly (avoiding temperature extremes) and to be cognizant of the expiration date.18 Lastly, the development of a written action plan for anaphylaxis is an important tool for managing this life-threatening condition.^16,20

Dr. Lieberman is a clinical professor of medicine and pediatrics in the Division of Allergy and Immunology at the University of Tennessee College of Medicine in Memphis, Tenn. This article was developed by Mylan Specialty, L.P.

References

1. Boyce JA, Assa’ad A, Burks AW, et al. Guidelines for the diagnosis and management of food allergy in the United States. Summary of the NIAID-sponsored expert panel report. U.S. Department of Health and Human Services. National Institutes of Health. National Institute of Allergy and Infectious Diseases. NIH Publication No. 11-7700. December 2010.
2. Branum AM, Lukacs SL. Food allergy among children in the United States. Pediatrics. 2009;124:1549-1555. Epub Nov 16.
3. Gupta RS, Springston EE, Warrier MR, et al. The prevalence, severity, and distribution of childhood food allergy in the United States. Pediatrics. 2011;128:e9-e17.
4. Decker WW, Campbell RL, Manivannan V, et al. The etiology and incidence of anaphylaxis in Rochester, Minnesota: a report from the Rochester Epidemiology Project. J Allergy Clin Immunol. 2008;122:1161-1165.
5. Bock SA, Muñoz-Furlong A, Sampson HA. Fatalities due to anaphylactic reactions to foods. J Allergy Clin Immunol. 2001;107:191-193.
6. Yocum MW, Butterfield JH, Klein JS, Volcheck GW, Schroeder DR, Silverstein MD. Epidemiology of anaphylaxis in Olmsted County: a population-based study. J Allergy Clin Immunol. 1999;104(2 Pt 1):452-456.
7. Lieberman P, Camargo CA Jr, Bohlke K, et al. Epidemiology of anaphylaxis: findings of the American College of Allergy, Asthma and Immunology Epidemiology of Anaphylaxis Working Group. Ann Allergy Asthma Immunol. 2006;97:596-602.
8. Ross MP, Ferguson M, Street D, Klontz K, Schroeder T, Luccioli S. Analysis of food-allergic and anaphylactic events in the National Electronic Injury Surveillance System. J Allergy Clin Immunol. 2008;121:166-171.
9. Pumphrey RSH. Lessons for management of anaphylaxis from a study of fatal reactions. Clin Exp Allergy. 2000;30:1144-1150.
10. Pumphrey R. Anaphylaxis: can we tell who is at risk of a fatal reaction? Curr Opin Allergy Clin Immunol. 2004;4:285-290.
11. Bock SA, Muñoz-Furlong A, Sampson HA. Further fatalities caused by anaphylactic reactions to food, 2001-2006. J Allergy Clin Immunol. 2007;119:1016-1018.
12. Sampson HA, Mendelson L, Rosen JP. Fatal and near-fatal anaphylactic reactions to food in children and adolescents. N Engl J Med. 1992; 327:380-384.
13. Branum AM, Lukacs SL. Food allergy among U.S. children: trends in prevalence and hospitalization. NCHS Data Brief. 2008;10:1-8.
14. Ring J, Behrendt H, de Weck A. History and classification of anaphylaxis. Chem Immunol Allergy. 2010;95:1-11.
15. Lieberman P, Ewan P. Anaphylaxis in Allergy. In: Holgate ST, Church MK, Broide DH, Martinez FD eds; Allergy. 4th ed. New York, NY: Elsevier Saunders; 2012:331-346.
16. Lieberman P, Nicklas RA, Oppenheimer J, et al. The diagnosis and management of anaphylaxis practice parameter: 2010 update. J Allergy Clin Immunol. 2010;126:477-480.
17. Lieberman P. Biphasic anaphylactic reactions. Ann Allergy Asthma Immunol. 2005; 95:217-226.
18. Kim H, Fischer D. Anaphylaxis. Allergy Asthma Clin Immunol. 2011;7(Suppl 1):S6.
19. Korenblat P, Lundie MJ, Dankner RE, Day JH. A retrospective study of epinephrine administration for anaphylaxis: how many doses are needed? Allergy Asthma Proc. 1999;20:383-386.
20. Simons FER, Ardusso LRF, Bilò MB, et al. World Allergy Organization guidelines for the assessment and management of anaphylaxis. WAO Journal. 2011;4:13-37.