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Anaphylaxis

Source: MedlinePlus Health Topics, U.S. National Library of Medicine

Last synced 8/9/2026Status: primary verified

Anaphylaxis is a serious allergic reaction . It can begin very quickly, and symptoms may be life-threatening. The most common causes are reactions to foods (especially peanuts), medications , and stinging insects . Other causes include exercise and exposure to latex . Sometimes no cause can be found. It can affect many organs: Skin - itching, hives, redness, swelling Nose - sneezing, stuffy nose, runny nose Mouth - itching, swelling of the lips or tongue Throat - itching, tightness, trouble swallowing, swelling of the back of the throat Chest - shortness of breath, coughing, wheezing, chest pain or tightness Heart - weak pulse, passing out, shock Gastrointestinal tract - vomiting, diarrhea, cramps Nervous system - dizziness or fainting If someone is having a serious allergic reaction, call 911. If an auto-injector is available, give the person the injection right away.

Educational only
This information is for general education and is not medical advice. Always talk to a licensed U.S. clinician about your situation, medications, or treatment decisions.