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Anaphylaxis
Anaphylaxis as a cause of sudden death
Sudden death is an instant unexpected death, which occurs within one hour of an abrupt change in a person's stable clinical state. Most would associate sudden death with a ventricular tachyarrhythmia usually secondary underlying to coronary heart disease in the middle-aged and elderly person; or long QT syndrome and hypertrophic cardiomyopathy in children and young athletes.
However, unknown to many, allergic diseases leading to anaphylaxis can be a cause of sudden death.
What is anaphylaxis?
What is anaphylaxis? Unfortunately, a universal definition of anaphylaxis is not available. Without a common understanding and a strict use of terms to define allergic disease, neither research nor patient care can be optimal.
Therefore, World Allergy Organization (WAO) proposed a revised nomenclature for allergy recommended for global use in October 2003.1 In this report, WAO recognized that physicians throughout the world use the term anaphylaxis differently.
It was proposed that anaphylaxis is defined as a severe, life-threatening generalized or systemic hypersensitivity reaction. The term allergic anaphylaxis should be used when the reaction is mediated by an immunologic mechanism, e.g. IgE, IgG and immune complex complement-related.
Anaphylaxis from whatever nonimmunologic cause should be referred to as nonallergic anaphylaxis. Previous terminology such as anaphylactoid reaction referring to non-IgE mediated reaction should preferably not be used.
Common causes of anaphylaxis
What are the common causes of anaphylaxis? The epidemiology of anaphylaxis in the Western Countries has been described in several studies.2-3 In these studies, the common causes of IgE-mediated allergic anaphylaxis include drugs, insect stings, food and natural rubber latex while non-steroidal anti-inflammatory drugs and radio contrast media are common causes of non-allergic anaphylaxis.
However, most of these studies were retrospective studies consisting of adult cohorts from specialty center using different inclusion criteria and methodology.
Therefore the true incidence and prevalence of anaphylaxis worldwide remains unknown.
Incidence of anaphylaxis in
In
A study done in
Compared to the Western studies, there were no cases of anaphylaxis due to drugs in particular beta-lactam antibiotics or natural rubber latex. The pattern of food-induced anaphylaxis was also different from Caucasian studies.
Seafood (crustaceans and mollusks e.g. limpet) comprised 66.7% of food-induced anaphylaxis. Another unusual allergen was bird’s nest. Anaphylaxis to peanut, tree nuts, fruits and vegetables were not as prevalent as in the Caucasian studies.
Treatment
Accurate diagnosis and identification of the culprit allergens causing anaphylaxis is important, as this would allow our patient to avoid the putative allergens.
Self-injectable adrenaline remains the main stay of treatment in the event of accidental ingestion leading to food anaphylaxis; and sting in patients with insect venom anaphylaxis. In those patients with insect venom anaphylaxis, insect venom immunotherapy is a proven therapy with 97% efficacy.5-6
References
1. Johansson SG, Bieber T, Dahl R, Friedmann PS, Lanier BQ, Lockey RF, et al. Revised nomenclature for allergy for global use: Report of the Nomenclature Review Committee of the World Allergy Organization, October 2003. J Allergy Clin Immunol 2004; 113:832-6
2. Kemp SF, Lockey RF. Anaphylaxis: a review of causes and mechanisms. J Allergy Clin Immunol 2002; 110:341-8
3. Yocum MW, Khan DA. Assessment of patients who have experienced anaphylaxis: a 3-year survey. Mayo Clin Proc 1994; 69:16-23.
4. Thong BY, Cheng YK, Leong KP, Tang CY, Chng HH. Anaphylaxis in adults referred to a clinical immunology/allergy centre in
5. Bousquet J, Lockey R, Malling HJ. Allergen immunotherapy: therapeutic vaccines for allergic diseases. A WHO position paper. J Allergy Clin Immunol 1998; 102:558-62
6. Kevin Hunt J et al. A controlled trial of immunotherapy in insect hypersensitivity. N Eng J Med 1978; 299:157-161
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