Anaphylaxis is a severe, whole-body allergic reaction. It can occur within seconds or minutes after the contact of the allergen. Common causes include insect bites, foods, and medications.
During anaphylaxis, a large amount of chemicals is released by your immune system and can cause you to go into shock; your blood pressure drops rapidly and your airways contracts thus blocking normal breathing. It typically results in a number of symptoms including an itchy rash, throat swelling, and low blood pressure.
Anaphylaxis is an emergency condition requiring immediate professional medical attention, including an injection of epinephrine and a trip to a hospital emergency room. If it isn’t treated properly, anaphylaxis can be fatal.