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Severe Allergic Reaction (Anaphylactic Shock) (cont.)

What Are Signs and Symptoms of a Severe Allergic Reaction?

The symptoms of anaphylaxis can vary. In some people, the reaction begins very slowly, but in most the symptoms appear rapidly and abruptly.

  • The most severe and life-threatening symptoms are difficulty breathing and loss of consciousness.
    • Difficulty breathing is due to swelling and/or spasm in the airways (which can include swelling of the tongue or the large and small parts of the airways). In very rare cases, breathing can stop altogether.
    • Loss of consciousness is due to dangerously low blood pressure, which is called "shock."
    • In the most serious cases, the heart can stop pumping altogether.
    • These events can lead to death from anaphylaxis.
  • While some symptoms are life threatening, others are merely uncomfortable. Generally, a reaction must involve at least two different body systems, such as skin and heart, to be considered anaphylaxis.
    • Skin: Most anaphylactic reactions involve the skin.
      • Hives (urticaria, welts, or wheals [raised bumps]): Hives can cause severe itching
      • Generalized erythema (redness)
      • Swelling in the face, eyelids, lips, tongue, throat, hands, and feet
      • Angioedema
    • Breathing: Swelling of the surrounding tissues narrows the airways.
      • Difficulty breathing, wheezing, chest tightness
      • Coughing, hoarseness
      • Nasal congestion, sneezing
    • Cardiovascular: Blood pressure may drop to dangerously low levels.
      • Rapid or irregular heart beat
      • Dizziness, faintness
      • Loss of consciousness, collapse
    • General
Medically Reviewed by a Doctor on 10/11/2017
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