ana·​phy·​lax·​is | \ ˌa-nə-fə-ˈlak-səs How to pronounce anaphylaxis (audio) \
plural anaphylaxes\ ˌa-​nə-​fə-​ˈlak-​ˌsēz How to pronounce anaphylaxes (audio) \

Definition of anaphylaxis

1 : hypersensitivity (as to foreign proteins or drugs) resulting from sensitization following prior contact with the causative agent

Examples of anaphylaxis in a Sentence

Recent Examples on the Web These allergies are believed to cause more deaths from anaphylaxis — an acute physiological response that includes lowered blood pressure, shock and constriction of the airways — than any other food allergy, though the precise number is not known., "The drug’s goal is not to cure the allergy, but to reduce the risk that an accidental exposure to small amounts of peanut will trigger a life-threatening reaction. It might also relieve some of the fear and anxiety of many families struggling to cope with a child’s severe peanut allergy.," 14 Sep. 2019 The most severe reaction is anaphylaxis, when the entire body responds with symptoms including impaired breathing, a sudden drop in blood pressure, and fainting and dizziness. Nadia Kounang And Steve Almasy, CNN, "FDA takes major step toward approving first peanut allergy treatment," 13 Sep. 2019 More severe reactions to allergy tablets, like anaphylaxis, are rare yet possible. Beth Krietsch, SELF, "Can Allergy Tablets Make Your Life Less Miserable?," 20 Aug. 2019 More than 40% of children with food allergies have experienced a severe reaction such as anaphylaxis, the group said. Bloomberg News, oregonlive, "What’s behind the persistent shortage of lifesaving EpiPens?," 23 Aug. 2019 There have been rare cases of allergic reaction, or anaphylaxis, related to the HPV shot, according to the CDC. Anna Almendrala, NBC News, "When parents say 'no' to HPV shots, teens have no choice. Some states are changing that.," 18 Aug. 2019 That's a sign the person was experiencing anaphylaxis, a life-threatening allergic reaction. NBC News, "More than 1.5 million Americans could have a sesame allergy," 2 Aug. 2019 Not unlike the symptoms of a peanut, egg, tree nut or a shellfish allergy, many people who are allergic to red meat may experience hives, a skin rash or anaphylaxis. Fox News, "Lone Star tick, known to cause red meat allergy, found in northern Wisconsin: report," 30 June 2019 Epi pens Students with severe allergies at risk of anaphylaxis can now possess and use a single-dose auto-injectable container of epinephrine while at school., "Here are the changes Alabama lawmakers made to schools this year," 22 June 2019

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'anaphylaxis.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

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First Known Use of anaphylaxis

circa 1905, in the meaning defined at sense 1

History and Etymology for anaphylaxis

New Latin, from ana- + prophylaxis

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Time Traveler for anaphylaxis

Time Traveler

The first known use of anaphylaxis was circa 1905

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Statistics for anaphylaxis

Cite this Entry

“Anaphylaxis.” The Dictionary, Merriam-Webster Inc., Accessed 6 December 2019.

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More Definitions for anaphylaxis


ana·​phy·​lax·​is | \ ˌan-ə-fə-ˈlak-səs How to pronounce anaphylaxis (audio) \
plural anaphylaxes\ -​ˌsēz How to pronounce anaphylaxes (audio) \

Medical Definition of anaphylaxis

1 : hypersensitivity (as to foreign proteins or drugs) resulting from sensitization following prior contact with the causative agent

More from Merriam-Webster on anaphylaxis

Britannica English: Translation of anaphylaxis for Arabic Speakers Encyclopedia article about anaphylaxis

Comments on anaphylaxis

What made you want to look up anaphylaxis? Please tell us where you read or heard it (including the quote, if possible).


very cautious or careful

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