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 pulse, skin rash, nausea and vomiting. Common triggers include certain foods, some medications and insect venom. Managing anaphylaxis requires injection of epinephrine. 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.