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Severe Allergic Reaction
(Anaphylactic Shock)

What Is a Severe Allergic Reaction?

  • Anaphylaxis is a severe allergic reaction that occurs rapidly and causes a life-threatening response involving the whole body. This reaction can lead to difficulty breathing and shock ultimately leading to death.
  • Most frequently, severe allergic reactions occur due to reactions to food, insect stings, or medications (immunologic causes), but they can also occur due to non-immunologic causes.
  • For an anaphylactic reaction to occur, you must have been exposed in the past to the substance that causes the reaction, called the antigen. This is called "sensitization."
  • Another bee sting may produce a sudden, severe allergic reaction known as anaphylaxis or anaphylactic shock.
  • These reactions usually occur within seconds to minutes of exposure. Occasionally, they are delayed.
  • You may develop sensitivity and anaphylaxis to a substance that you have been exposed to many times in the past without a reaction, and often people don't recall the previous exposure.
Medically Reviewed by a Doctor on 10/11/2017
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