Anaphylaxis (say "ann-uh-fuh-LAK-suss") is a severe allergic reaction that affects the entire body (systemic). It can occur within a few seconds or minutes after a person is exposed to a substance (allergen or antigen).
Symptoms and signs of a severe allergic reaction may include:
- Raised, red bumps on the skin (hives or wheals).
- Wheezing or difficulty breathing.
- Rapid swelling, either in one area or over the entire body. Swelling is most serious when it involves the lips, tongue, mouth, or throat and interferes with breathing.
- Abdominal pain or cramps.
- Nausea or vomiting.
- Low blood pressure, shock, and unconsciousness.
The sooner symptoms occur after exposure to the substance, the more severe the anaphylactic reaction is likely to be. An anaphylactic reaction may occur with the first exposure to an allergen, with every exposure, or after several exposures. An anaphylactic reaction can be life-threatening and is a medical emergency. Emergency care is always needed for an anaphylactic reaction.
Current as of: March 12, 2014
Author: Healthwise Staff
Medical Review: William H. Blahd, Jr., MD, FACEP - Emergency Medicine & H. Michael O'Connor, MD - Emergency Medicine
Public Health Alerts
Public health alerts include information about outbreaks, advisories and product recalls. Click on the links below to read the most recent alerts, or visit our Public Health Alerts web page.
FIND Services and Resources
If you are looking for health services in your community, you can use our directory to FIND hospitals, clinics, and other resources.
To learn more, visit Healthwise.org
© 1995-2014 Healthwise, Incorporated. Healthwise, Healthwise for every health decision, and the Healthwise logo are trademarks of Healthwise, Incorporated.
Is it an emergency?
If you or someone in your care has chest pains, difficulty breathing, or severe bleeding, it could be life-threatening. Call 9-1-1 or the local emergency number immediately. If you are concerned about a possible poisoning or exposure to a toxic substance, call Poison Control now at 1-800-567-8911.