Anaphylaxis (also known as anaphylactic shock or reaction) is an acute severe systemic hypersensitivity reaction, commonly presenting with urticaria/angioedema, hypotension and bronchial hyperreactivity. It may be fatal.
Anaphylactoid reactions result from non-immune system mediated mechanisms. However they are clinically indistinguishable from anaphylactic reactions with similar risks of multiorgan failure and death. From a patient perspective anaphylactoid and anaphylactic reactions are managed identically 5.
The published epidemiological data from the USA, UK and Australia, demonstrates an incidence rate of anaphylaxis of 7 to 50 cases per 100,000 per annum. The number of deaths is estimated to be up to 3 per 1,000,000 per year.
There is no gender preference in adults; in prepubescent children, it is more common in boys 1.
The typical presentation affects the skin, chest, GI tract and cardiovascular system. Often the signs and symptoms are indolent in onset and initially mild, such as itching and rashes.
- systemic hypotension
However, up to 20% patients with anaphylaxis lack any evidence of circulatory compromise or dermatological sequelae 2.
In radiology, approximately 1 in 40,000 patients will experience anaphylaxis from iodinated contrast media. Most anaphylaxis will occur within twenty minutes of administration of IV contrast agents, although longer delays are occasionally seen.
- 1. Ring J, Beyer K, Biedermann T, Bircher A, Duda D, Fischer J, Friedrichs F, Fuchs T, Gieler U, Jakob T, Klimek L, Lange L, Merk HF, Niggemann B, Pfaar O, Przybilla B, Ruëff F, Rietschel E, Schnadt S, Seifert R, Sitter H, Varga EM, Worm M, Brockow K. Guideline for acute therapy and management of anaphylaxis: S2 Guideline of the German Society for Allergology and Clinical Immunology (DGAKI), the Association of German Allergologists (AeDA), the Society of Pediatric Allergy and Environmental Medicine (GPA), the German Academy of Allergology and Environmental Medicine (DAAU), the German Professional Association of Pediatricians (BVKJ), the Austrian Society for Allergology and Immunology (ÖGAI), the Swiss Society for Allergy and Immunology (SGAI), the German Society of Anaesthesiology and Intensive Care Medicine (DGAI), the German Society of Pharmacology (DGP), the German Society for Psychosomatic Medicine (DGPM), the German Working Group of Anaphylaxis Training and Education (AGATE) and the patient organization German Allergy and Asthma Association (DAAB). (2014) Allergo journal international. 23 (3): 96-112. doi:10.1007/s40629-014-0009-1 - Pubmed
- 2. Tupper J, Visser S. Anaphylaxis: A review and update. (2010) Canadian family physician Medecin de famille canadien. 56 (10): 1009-11. Pubmed
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- 4. Reber LL, Hernandez JD, Galli SJ. The pathophysiology of anaphylaxis. (2017) The Journal of allergy and clinical immunology. 140 (2): 335-348. doi:10.1016/j.jaci.2017.06.003 - Pubmed
- 5. Lagopoulos V, Gigi E. Anaphylactic and anaphylactoid reactions during the perioperative period. (2011) Hippokratia. 15 (2): 138-40. Pubmed