Anaphylaxis: Symptoms, Causes, and Emergency Treatment

Anaphylaxis is a severe, potentially life-threatening allergic reaction that can develop within seconds to minutes after allergen exposure. It results from massive release of histamine and other mediators from mast cells and basophils.

Common Symptoms

• Difficulty breathing, wheezing
• Swelling of face, lips, tongue, throat (angioedema)
• Hives, itching, flushing
• Nausea, vomiting, diarrhea, abdominal pain
• Lightheadedness, dizziness, fainting
• Rapid, weak pulse
• Sense of impending doom

Emergency Response

Anaphylaxis is a medical emergency. Administer epinephrine (adrenaline) via auto-injector immediately, then call 911. The patient should lie flat with legs elevated. A second dose of epinephrine may be needed if symptoms persist after 5–15 minutes. Even if symptoms improve, emergency department evaluation is mandatory due to risk of biphasic reaction.