Anaphylaxis is a severe, potentially life-threatening allergic reaction. It can occur within seconds or minutes of exposure to something you're allergic to, such as peanuts or bee stings.
Anaphylaxis causes your immune system to release a flood of chemicals that can cause you to go into shock — your blood pressure drops suddenly and your airways narrow, blocking breathing. Signs and symptoms include a rapid, weak pulse; a skin rash; and nausea and vomiting. Common triggers include certain foods, some medications, insect venom and latex.
Anaphylaxis requires an injection of epinephrine and a follow-up trip to an emergency room. If you don't have epinephrine, you need to go to an emergency room immediately. If anaphylaxis isn't treated right away, it can be fatal.
Symptoms Anaphylaxis symptoms usually occur within minutes of exposure to an allergen. Sometimes, however, it can occur a half-hour or longer after exposure. Signs and symptoms include:
Skin reactions, including hives and itching and flushed or pale skin Low blood pressure (hypotension) Constriction of your airways and a swollen tongue or throat, which can cause wheezing and trouble breathing A weak and rapid pulse Nausea, vomiting or diarrhea Dizziness or fainting
