Anaphylaxis

Abstract

Anaphylaxis is a sudden onset, immediate reaction that implies a risk of death. Think of a “rule of 2s” for anaphylaxis, which implies that reactions usually begin within 2 minutes to 2 hours after injection, infusion, ingestion, contact, or inhalation. Fatalities can be from asphyxiation from laryngeal or oropharyngeal swelling, collapse from hypotensive shock, cardiac arrest, or acute severe bronchoconstriction that causes respiratory failure and arrest. When there is activation of mast cells and basophils in anaphylaxis, chemical mediators are detectable. The preformed mediators from mast cells include histamine, tryptase, carboxypeptidase A, and proteoglycans (heparin, chondroitin sulfates). Newly synthesized mediators include prostaglandin D2, leukotriene D4, and platelet activating factor. Crucial actions of the mediators include an abrupt increase in vascular permeability, vascular smooth muscle relaxation, and bronchial smooth muscle contraction. Anaphylaxis can be classified into immunologic, nonimmunologic, or idiopathic based on the associated mechanism. For example, immunologic causes of anaphylaxis are those mediated by immunoglobulin E (IgE) antibodies acting through the FcεR I (foods, insect venom, 32 β-lactam antibiotics), whereas non-IgE immunologic anaphylaxis is mediated without the presence of anti-allergen IgE antibodies or via FcεRI activation (radiographic contrast material). Nonimmunologic anaphylaxis involves mast cell mediator release such as occurs with exercise or with cold temperature exposure, or from medications such as opioids or vancomycin. Idiopathic anaphylaxis involves mast cell activation (acutely elevated urine histamine or serum tryptase) and activated lymphocytes. Because anaphylaxis is a medical emergency, the drug of choice is epinephrine, not H1 antihistamines or H2 receptor antagonists.

Vaccines and allergic reactions: The past, the current COVID‐19 pandemic, and future perspectives

“…Idiopathic anaphylaxis is diagnosed through exclusion of other known causes and may mask a clonal mast cell disorder. [18][19][20][21][22][23] Non-immunological anaphylaxis was previously termed anaphylactoid reactions, but the World Allergy Organization (WAO) in 2004 suggested replacing anaphylactoid reactions with non-immunological anaphylaxis. 24 The change in terminology is to reinforce the risk and potential fatality of all types of anaphylaxis, regardless of the underlying mechanism.…”

“…[68][69][70] While radio-contrast agents have traditionally been considered to be non-immunologic, some of the newer, lowosmolar agents may induce IgE-mediated reactions. 21 Although the clinical presentations of both IgE-mediated anaphylaxis and non-immunologic anaphylaxis are similar, measurements of tryptase and SC5b-9may assist in differentiating the two types. 71,72 Tryptase is a marker of mast cell activation which is released following mast cell degranulation while SC5b-9 is a marker of complement activation and is a terminal complement complex.…”

“…Anaphylaxis can be either immunological, non‐immunological, or idiopathic. Idiopathic anaphylaxis is diagnosed through exclusion of other known causes and may mask a clonal mast cell disorder 18–23 . Non‐immunological anaphylaxis was previously termed anaphylactoid reactions, but the World Allergy Organization (WAO) in 2004 suggested replacing anaphylactoid reactions with non‐immunological anaphylaxis 24 .…”

“…Since 2015, evidence has accumulated that off‐target occupation of this receptor by different therapy regimens, such as neuromuscular blocking agents (NMBA) and opioids could constitute an additional mechanism of non‐immune immediate drug hypersensitivity. 68–70 While radio‐contrast agents have traditionally been considered to be non‐immunologic, some of the newer, low‐osmolar agents may induce IgE‐mediated reactions 21 …”

A Case of Cardiac Arrest Soon after Receiving a Sting from a Wasp

“…Fatalities can occur due to asphyxiation from laryngeal or oropharyngeal swelling, collapse from hypotensive shock, cardiac arrest, or acute severe bronchoconstriction that causes respiratory failure and arrest. [1] Bee or wasp stings can result in a fatal outcome due to anaphylactic reaction. [2] We herein report a case of cardiac arrest soon after receiving one sting from a wasp.…”