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What Is Anaphylaxis?

If you have a food allergy, there is a chance that you may experience a severe form of allergic reaction known as anaphylaxis. Anaphylaxis may begin suddenly and may lead to death if not immediately treated.

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Anaphylaxis includes a wide range of symptoms that can occur in many combinations. Some symptoms are not life-threatening, but the most severe restrict breathing and blood circulation.

Many different parts of your body can be affected:

  • Skin—itching, hives, redness, swelling
  • Nose—sneezing, stuffy nose, runny nose
  • Mouth—itching, swelling of lips or tongue
  • Throat—itching, tightness, difficulty swallowing, hoarseness
  • Chest—shortness of breath, cough, wheeze, chest pain, tightness
  • Heart—weak pulse, passing out, shock
  • Gastrointestinal (GI) tract—vomiting, diarrhea, cramps
  • Nervous system—dizziness or fainting

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How soon after exposure will symptoms occur?

Symptoms may begin within several minutes to several hours after exposure to the food. Sometimes the symptoms go away, only to return two to four hours later or even as many as eight hours later. When you begin to experience symptoms, seek immediate medical attention because anaphylaxis can be life-threatening.

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Can anaphylaxis be predicted?

Anaphylaxis caused by an allergic reaction to a certain food is highly unpredictable. The severity of a given attack does not predict the severity of subsequent attacks. The response will vary depending on several factors, such as the following:

  • Your sensitivity to the food
  • How much of the food you are exposed to
  • How the food entered your body

Any anaphylactic reaction may become dangerous and must be evaluated immediately by a healthcare professional.

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What can cause anaphylaxis?

Food allergy is the leading cause of anaphylaxis; however, medications, insect stings, and latex can also cause an allergic reaction that leads to anaphylaxis.

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How do you know if a person is having an anaphylactic reaction?

Anaphylaxis is highly likely if at least one of the following three conditions occurs:

  1. Within minutes or several hours of the onset of an illness, a person has skin symptoms (redness, itching, hives) or swollen lips and either difficulty breathing or a drop in blood pressure
  2. A person was exposed to an allergen likely to cause an allergic reaction and, within minutes or several hours, two or more of the following symptoms occur:
    • Skin symptoms or swollen lips
    • Difficulty breathing
    • A drop in blood pressure
    • GI symptoms such as vomiting, diarrhea, or cramping
  3. A person exposed to an allergen that is previously known to cause an allergic reaction in that person experiences a drop in blood pressure.

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Last Updated December 06, 2010

Last Reviewed November 02, 2010