I've mentioned the word "anaphylaxis" in this blog innumerable times and I just realized that I haven't really devoted an entry defining exactly just what it is. In parallel, I have created a new category called "Allergy Basics" where all, well, basic stuff about allergies would be filed under.

So, what is anaphylaxis, then?

According to the MedlinePlus Medical Encyclopedia:

Anaphylaxis is an acute systemic (whole body) type of allergic reaction which occurs when a person has become sensitized to a certain substance or allergen and is again exposed to the allergen. [snip] Histamines and other substances released into the bloodstream cause blood vessels to dilate and tissues to swell. Anaphylaxis may be life-threatening if obstruction of the airway occurs, if blood pressure drops, or if heart arrhythmias occur.

The dangerous aspect of anaphylaxis is that it can occur suddenly, and the symptoms are severe because it involves the whole body. It is an emergency condition, which requires professional medical attention. Left unattended, it may lead to shock, and possibly death. Although it is generally believed that it occurs infrequently, its unpredictability and graveness causes much anxiety and fear among the fears of people with allergies.

Epinephrine injections, commercially available under the brand name Epi-Pen, are given as first aid.

Learn more about the symptoms, incidence and risk factors from MedlinePlus.