idiopathic anaphylaxis information center

a resource for people with ia and other mast cell disorders

Basic terms:


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What is anaphylaxis?

Photograph of lightning striking in Australia; source: Wikimedia Commons

“Anaphylaxis is a serious allergic reaction that is rapid in onset and may cause death.”

It would not surprise me if you read the above definition [Sampson HA, Muñoz-Furlong A, et al. Second symposium on anaphylaxis. J Allergy Clin Immunol. 2006; 117:391–7] and think, “Okay, so ana–whatever-you-call-it is this really bad thing that can kill someone. But what is it, exactly? What exactly happens? How can I know if it's happening to me?”

The same specialists [Sampson HA, Muñoz-Furlong A, et al. Second symposium on anaphylaxis. J Allergy Clin Immunol. 2006; 117:391–7] who crafted the above statement admit: "Even though anaphylaxis was first described around 100 years ago and is one of the most alarming disorders encountered in medicine, there is no universal agreement on its definition or criteria for diagnosis."

Why? How could something have been known for over a century and still be so poorly understood? One big problem in researching anaphylaxis was summed up almost thirty years ago: “Since these reactions are usually unexpected and occasionally fatal, opportunities to investigate systematically the detailed pathophysiology [functional disturbance causing disease] with controlled studies are exceedingly rare.” Reference [Smith PL, Kagey-Sobotka A, et al. Physiologic manifestations of human anaphylaxis. J Clin Invest. 1980;66:1072–80].

In other words, how can scientists study a phenomenon when it doesn’t reliably happen and it can kill your subjects? Rigorous research requires a certain degree of control over the thing being studied. Anaphylaxis is the physiological equivalent of lightning — you never know just when or where it will happen, but the likelihood that its effects can be devastating are very high.

A recent review of our knowledge of anaphylaxis ominously noted: "...It is clear that anaphylaxis is not rare and that the rate of occurrence is increasing, especially in the first two decades of life." Reference [Simons FER. Anaphylaxis: Recent advances in assessment and treatment. JACI. 2009; 124:625–36].

Page last updated: January 18, 2012

All information contained in this site is one layperson's interpretation of medical journal articles, textbooks, seminars, presentations, and other materials. Nothing that is stated here should carry more weight than the informed and considered opinions of your own highly trained and qualified medical caregivers. The author of this site is not a doctor and has absolutely no authority to prescribe or diagnose.

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