Presse Med
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Allergy to neuromuscular blocking agents (NMBAs) has been the first cause of perioperative anaphylaxis for decades, in most countries. The most frequently involved agents are suxamethonium and rocuronium. ⋯ In cases of true allergy, assessing cross-reactivity to other NMBAs is mandatory. The cross-sensitization hypothesis is presently being investigated and if confirmed, it could allow primary prevention measures to be implemented.
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Anaphylactic reactions may be either of immune (allergy, usually IgE-mediated, sometimes IgG-mediated) or non-immune origin. The incidence of anaphylactic reactions during anaesthesia varies between countries ranging from 1/1250 to 1/18,600 per procedure. In France, the estimated incidence of allergic reactions is 100.6 [76.2-125.3]/million procedure with a high female predominance (male: 55.4 [42.0-69.0], female: 154.9 [117.2-193.1]). ⋯ Reactions involving antibiotics, dyes or chlorhexidine are reported with a high and sometimes increasing frequency in most series. Reactions to latex are rapidly decreasing as a result of primary and secondary prevention policy. Regional differences are a strong incentive for repeated epidemiological surveys in different countries.
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The incidence of allergic reactions to local anesthetics is low. Most cases involve a psychogenic reaction rather than an allergic reaction. ⋯ Vascular resorption of epinephrine-containing local anesthetics may produce cardiovascular signs similar to an allergic reaction. Diagnosis of allergy to local anesthetics must be established by skin testing and provocative challenge.
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The diagnosis of a perioperative allergic reaction is based on clinical features associated with a suggestive timeline, the exclusion of other diagnoses, elevated concentrations of degranulation markers (histamine, tryptase), and positive allergy assessments (skin tests, specific IgE). After initiating appropriate treatment, the anesthesiologist should take blood samples to measure histamine and tryptase concentrations just after the reaction and repeat them 1-2hours later to validate the diagnosis of immediate hypersensitivity. A delayed measurement of basal tryptase is useful to rule out mastocytosis and to interpret moderate tryptase levels. ⋯ Provocation tests are sometimes required. After allergy assessment, the safest protocol for subsequent anesthesia is determined in collaboration with the anesthesiologist. The patient must be informed and carry an allergy alert card.