anaphylaxis

noun

ana·​phy·​lax·​is ˌa-nə-fə-ˈlak-səs 

plural anaphylaxes ˌa-nə-fə-ˈlak-ˌsēz 

1

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

2

: anaphylactic shock

Examples of anaphylaxis in a Sentence

Recent Examples on the Web

Jones noted that sesame is now recognized as one of the nine major food allergens in the United States, and allergic reactions can range from mild itching or hives to life-threatening anaphylaxis. — Daryl Austin, USA Today, 12 Aug. 2026

Allergic reactions and anaphylaxis have been reported in patients using bee venom therapy. — Stephanie Brown, Verywell Health, 19 June 2026

Avoid triggers, but carry an epinephrine pen for emergency treatment of anaphylaxis for when triggers are unavoidable or unknown. — Ruth Jessen Hickman, Health, 12 June 2026

Some people are allergic to different venoms, and could experience life-threatening anaphylaxis without immediate treatment. — Sophie Lindberg, Kansas City Star, 10 June 2026

Word History

Etymology

New Latin, from ana- + prophylaxis

First Known Use

circa 1905, in the meaning defined at sense 1

Rhymes for anaphylaxis

• axis
• praxis
• taxus
• chemoprophylaxis
• chemotaxis
• epistaxis
• prophylaxis

Medical Definition

anaphylaxis

noun

ana·​phy·​lax·​is ˌan-ə-fə-ˈlak-səs 

plural anaphylaxes -ˌsēz 

1

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

2

: anaphylactic shock