anaphylaxis

American  

[an-uh-fuh-lak-sis] / ˌæn ə fəˈlæk sɪs /

noun

Pathology.

1. exaggerated allergic reaction to a foreign protein resulting from previous exposure to it.

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anaphylaxis British  

/ ˌænəfɪˈlæksɪs /

noun

1. extreme sensitivity to an injected antigen, esp a protein, following a previous injection

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anaphylaxis Scientific  

/ ăn′ə-fə-lăk′sĭs /

1. See anaphylactic shock

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Other Word Forms

• anaphylactic adjective
• anaphylactically adverb
• antianaphylactic adjective
• pseudoanaphylactic adjective

Etymology

Origin of anaphylaxis

First recorded in 1905–10; ana- + (pro)phylaxis

Compare meaning

How does anaphylaxis compare to similar and commonly confused words? Explore the most common comparisons:

• anaphylaxis vs. anaphylactic shock

Example Sentences

Baxter was not given anti-venom over concerns about his breathing and possible side effects, which can include anaphylaxis.

From BBC • Apr. 24, 2026

The results also pointed to an extreme immune response consistent with fatal anaphylaxis.

From Science Daily • Dec. 17, 2025

The immune system tries to fight them off, triggering symptoms ranging from hives and diarrhea to anaphylaxis, a life-threatening condition.

From Los Angeles Times • Oct. 20, 2025

Among the most common co-occurring illnesses were chronic fatigue syndrome and mast cell activation syndrome, or MCAS, a condition where patients experience intense episodes of diarrhea, hives, vomiting, and, in many cases, life-threatening anaphylaxis attacks.

From Slate • Sep. 15, 2025

Another and most interesting phase of my subject is the relation of nut feeding to anaphylaxis.

From Northern Nut Growers Association, report of the proceedings at the eighth annual meeting Stamford, Connecticut, September 5 and 6, 1917 by Northern Nut Growers Association