Health Library

The Health Library is a collection of health and wellness resources created for learning and accessibility. Select a topic below for related health information or search for a topic in the search bar for more information on other medical conditions.

Spanish Translation

Allergic Reaction Symptoms, Severe (Anaphylaxis)

Symptoms of a severe allergic reaction (anaphylaxis) may include:

  • The sudden appearance of raised, red areas (hives) all over the body.
  • Rapid swelling of the throat, mouth, or tongue.
  • Trouble breathing.
  • Passing out (losing consciousness). Or you may feel very lightheaded or suddenly feel weak, confused, or restless.
  • Severe belly pain, nausea, vomiting, or diarrhea.

A severe reaction can be life-threatening. If you have had a bad allergic reaction to a substance before and are exposed to it again, treat any symptoms as an emergency. Even if the symptoms are mild at first, they may quickly become very severe.

Current as of: October 24, 2023

Author: Ignite Healthwise, LLC Staff

Clinical Review Board
All Healthwise education is reviewed by a team that includes physicians, nurses, advanced practitioners, registered dieticians, and other healthcare professionals.

This information does not replace the advice of a doctor. Ignite Healthwise, LLC, disclaims any warranty or liability for your use of this information. Your use of this information means that you agree to the Terms of Use. Learn how we develop our content.