One study in children found that 60% had a history of previous atopic diseases, and of children who die from anaphylaxis, more than 90% have asthma. Those with mastocytosis or of a higher socioeconomic status are at increased risk. Pathophysiology
Anaphylaxis is a severe allergic reaction of rapid onset affecting many body systems. It is due to the release of inflammatory mediators and cytokines from mast cells and basophils, typically due to an immunologic reaction but sometimes non-immunologic mechanism.Interleukin (IL)–4 and IL-13 are cytokines important in the initial generation of antibody and inflammatory cell responses to anaphylaxis. 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 muscles, trigger vasodilation, increase the leakage of fluid from blood vessels, and cause heart muscle depression. There is also a non-immunologic mechanism that does not rely on IgE, but it is not known if this occurs in humans. Non-immunologic
Non-immunologic mechanisms involve substances that directly cause the degranulation of mast cells and basophils. These include agents such as contrast medium, opioids, temperature (hot or cold), and vibration. Sulfites may cause reactions by both immunologic and non-immunologic mechanisms. Diagnosis
Anaphylaxis is diagnosed on the basis of a persons signs and symptoms.
Research
There are ongoing efforts to develop sublingual epinephrine to treat anaphylaxis. Trials of sublingual epinephrine, currently called AQST-108 (dipivefrin) and sponsored by Aquestive Therapeutics, are in phase 1 trials as of December 2021. Subcutaneous injection of the anti-IgE antibody omalizumab is being studied as a method of preventing recurrence, but it is not yet recommended. References
External links

Anaphylaxis at Curlie
National Institute for Health and Clinical Excellence. Clinical guideline 134: Anaphylaxis: assessment to confirm an anaphylactic episode and the decision to refer after emergency treatment for a suspected anaphylactic episode. London, 2011. and Anaphylaxis pathway
"Anaphylaxis". MedlinePlus. U.S. National Library of Medicine.