Anaphylaxis is a severe, potentially life-threatening allergic reaction. It can occur within seconds or minutes of exposure to something you're allergic to, such as a peanut or the venom from a bee sting.

The flood of chemicals released by your immune system during anaphylaxis can cause you to go into shock; your blood pressure drops suddenly and your airways narrow, blocking normal breathing. Signs and symptoms of anaphylaxis include a rapid, weak pulse, a skin rash, and nausea and vomiting. Common triggers of anaphylaxis include certain foods, some medications, insect venom and latex.

Anaphylaxis requires an immediate trip to the emergency department and an injection of epinephrine. If anaphylaxis isn't treated right away, it can lead to unconsciousness or even death.

Symptoms Causes Risk factors Complications Prevention

Anaphylaxis symptoms usually occur within minutes of exposure to an allergen. Sometimes, however, anaphylaxis can occur a half-hour or longer after exposure. Anaphylaxis symptoms include:

  • Skin reactions, including hives along with itching, and flushed or pale skin (almost always present with anaphylaxis)
  • A feeling of warmth
  • The sensation of a lump in your throat
  • Constriction of the airways and a swollen tongue or throat, which can cause wheezing and trouble breathing
  • A weak and rapid pulse
  • Nausea, vomiting or diarrhea
  • Dizziness or fainting

When to see a doctor

Seek emergency medical help if you, your child or someone else you're with has a severe allergic reaction.

If the person having the attack carries an epinephrine autoinjector (such as an EpiPen or EpiPen Jr), give him or her a shot right away. Even if symptoms improve after an emergency epinephrine injection, a visit to the emergency department is still necessary to make sure symptoms don't return.

Make an appointment to see your doctor if you or your child has had a severe allergy attack or any signs and symptoms of anaphylaxis in the past.

The diagnosis and long-term management of anaphylaxis are complicated, so you'll probably need to see a doctor who specializes in allergies and immunology.

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