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Anaphylaxis



Anaphylactic shock is a severe allergic reaction which sends your body into shock, depleting it of oxygen. The body gets “shocked” when blood pressure drops and bodily cells (thus organs) do not receive sufficient oxygen. Symptoms range from the nasal area such as coughing and sneezing to dizziness or weakness. In some severe cases, anaphylaxis can lead to death.

An antigen crosslinks to IgE (Immunoglobulin E) and binds to the receptor on the Mast Cell. This is known as Cell signalling. When this happens, a cascade of reactions occur and Mast Cells releases histamine. Histamine increases the permeability and dilates blood vessels which causes blood pressure to drop, leading to shock. 

Inflamed tissue looks red because there is more blood in dilated blood vessels. Also, the increased permeability of blood vessels allows fluid to enter which causes swelling. As a result, the swelling increases the tension in nerve tissues by pressing against them, and this leads to itchy and/or skin rash.

The symptoms of anaphylactic shock are broad because it causes systemic inflammation. This explains why the symptoms can range from the Gastrointestinal Tract to the Cranial region. 

Anaphylaxis can be life threatening, but in reality the majority of symptoms do not result in severe outcomes. Fortunately, anaphylaxis is a rare event, with a fatality rate of under 0.001%.


https://www.mayoclinic.org/diseases-conditions/allergies/symptoms-causes/syc-20351497

https://www.webmd.com/allergies/anaphylactic-shock-facts

https://adc.bmj.com/content/104/1/83

https://www.researchgate.net/figure/Schematic-representation-of-the-pathophysiology-of-anaphylaxis-and-the-specific-role-of_fig1_327649185

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