Editing Anaphylaxis (section)

==Pathophysiology==
Anaphylaxis is a severe [[Allergy|allergic reaction]] of rapid onset affecting many [[Biological system|body systems]].<ref name=Tint10/><ref name=Khan11/> It is due to the release of [[Inflammation|inflammatory mediators]] and [[cytokine]]s from mast cells and [[Basophil granulocyte|basophils]], typically due to an [[Immune system|immunologic reaction]] but sometimes non-immunologic mechanism.<ref name=Khan11/>

[[Interleukin]] (IL)–4 and IL-13 are cytokines important in the initial generation of antibody and inflammatory cell responses to anaphylaxis.<ref name="v005"/>

===Immunologic===
In the immunologic mechanism, [[immunoglobulin E]] (IgE) binds to the [[antigen]] (the foreign material that provokes the allergic reaction). Antigen-bound IgE then activates [[FcεRI]] receptors on mast cells and basophils. This leads to the release of inflammatory mediators such as [[histamine]]. These mediators subsequently increase the contraction of bronchial [[Smooth muscle tissue|smooth muscles]], trigger [[vasodilation]], increase the leakage of fluid from blood vessels, and cause heart muscle depression.<ref name=Khan11/><ref name=Rosen2010/> There is also a non-immunologic mechanism that does not rely on IgE, but it is not known if this occurs in humans.<ref name=Khan11/>

===Non-immunologic===
Non-immunologic mechanisms involve substances that directly cause the [[degranulation]] of mast cells and basophils.<!-- <ref name=Khan11/> --> These include agents such as [[contrast medium]], [[opioid]]s, temperature (hot or cold), and vibration.<ref name=Khan11/><ref name=APLS07/> [[Sulfites]] may cause reactions by both immunologic and non-immunologic mechanisms.<ref>{{cite book|last1=Lewis|first1=Julius M.|last2=Cruse|first2=Robert E.|title=Atlas of immunology|date=2010|publisher=CRC Press/Taylor & Francis|location=Boca Raton, FL|isbn=9781439802694|page=411|edition=3rd|url=https://books.google.com/books?id=kNI5Lk2z37sC&pg=PA411|url-status=live|archive-url=https://web.archive.org/web/20170320104901/https://books.google.com/books?id=kNI5Lk2z37sC&pg=PA411|archive-date=2017-03-20}}</ref>