It can occur within seconds or minutes in sensitive individuals exposed to a specific allergy-causing substance. Almost any allergy-causing substance can cause the response, including insect venom, pollen, latex, certain foods and drugs.
Some people have anaphylactic reactions of unknown cause.
If you are extremely sensitive, you might break out in hives and your eyes or lips may swell severely. The inside of your throat may swell as well, possibly progressing to difficulty breathing and shock. Dizziness, mental confusion, abdominal cramping, nausea or vomiting may also accompany a severe allergic reaction. If you have had an anaphylactic reaction in the past, carry medications with you as an antidote. Epinephrine is the most commonly used drug for severe allergic reactions.