Kounis syndrome

Kounis syndrome, also known as allergic acute coronary syndrome, refers to an acute coronary syndrome accompanying mast cell activation from allergic, hypersensitivity, or anaphylactoid reactions.


It is represented by a vasospastic acute coronary syndrome with or without the presence of underlying coronary artery disease.

It is thought to be caused by inflammatory mediators such as neutral proteases (e.g. tryptase and chymase, arachidonic acid products, histamine, platelet activating factors etc.) released during the activation process.


Three types of KS have been described:

  • type I: patients with normal coronary arteries without predisposing factors for coronary artery disease in whom the acute allergic insult leads to coronary artery spasm with normal cardiac biomarkers or infarction with positive cardiac biomarkers
  • type II: patients with culprit but inactive preexisting atheromatous disease, in whom the allergic insult leads to plaque erosion or rupture, leading to acute myocardial infarction or coronary vasospasm with normal cardiac enzymes
  • type III: coronary artery stent thrombosis secondary to an allergic reaction 

History and etymology

It was first described by N G Kounis and Zavras in 1991.

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Article information

rID: 61893
System: Cardiac
Synonyms or Alternate Spellings:
  • Allergic acute coronary syndrome
  • Allergic myocardial infarction
  • Allergic angina

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