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
• antianaphylactic
  adjective
• pseudoanaphylactic
  adjective
• anaphylactically
  adverb

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

See Examples For:

anaphylaxis

If she had, doctors might have established that Jeremy had actually been suffering from anaphylaxis, and sent him home with an EpiPen.

From BBC ● Jul. 20, 2026

Scientists have long suspected that severe cases could escalate into life threatening 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

As lipoids do not cause anaphylaxis, there should be no difference in the reaction of normal and uremic sera unless in one there was some form of protein not in the other.

From Arteriosclerosis and Hypertension: with Chapters on Blood Pressure, 3rd Edition. by Warfield, Louis Marshall