Symptom Watch: Red Flags for Anaphylaxis
There's no time to second-guess if you're having anaphylaxis. Learn what symptoms to watch out for and what to do.

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Image of peanut butter jar and peanuts. Symptom Watch: Red Flags for Anaphylaxis

Anaphylaxis is an extreme, life-threatening allergic reaction. Symptoms appear in seconds or minutes. If you were lucky enough to survive a prior anaphylactic reaction, consider it a warning. Don't wait for your next "close call." See your doctor to have your allergy symptoms evaluated. And, know the red flags.

Red flags, body-wide
Symptoms of anaphylaxis usually start within seconds or minutes after exposure. Beware of any of the following signs of anaphylaxis:

The skin
Reactions almost always involve:

  • Hives, which are red, often itchy raised bumps on the surface of the skin
  • Flushing, or redness and warmth, especially in the face, neck and upper chest
  • Sweating

Eyes, nose and mouth

  • Swelling of the skin around the eyes, plus itchy, red eyes
  • Runny nose and congestion
  • Swelling of the lips and tongue
  • A possible metallic taste

Lungs and airways

  • Difficulty getting air in and out
  • Panting or rapid, shallow breathing
  • Coughing, chest tightness and wheezing
  • Increased mucous production
  • Throat swelling or itching
  • Hoarseness and/or change in voice
  • Sensation of choking


  • Rapid, thready pulse (not a distinct beat)
  • Drop in blood pressure (this may cause dizziness, lightheadedness or passing out)


  • Stomach cramping
  • Vomiting
  • Diarrhea

Nervous system

  • Anxiety.
  • A feeling described as "impending doom."
  • Dizziness.
  • Fainting. Sudden loss of consciousness may be the only symptom and can occur after a bee sting or following an injection with a medication.
  • Seizures.

Double whammy: the biphasic reaction
One percent to as many as 20 percent of people with anaphylaxis have a biphasic or delayed reaction. This means that symptoms go away at first. Then, within eight to 72 hours, without further exposure to the trigger, symptoms return. So if you have a "close call" or severe allergic reaction and symptoms subside, you should still seek emergency help.

What to do?
Anaphylaxis is a medical emergency. Call 9-1-1 right away.

If you are having a severe allergic reaction - or are with someone who is - call 9-1-1 to seek emergency medical help.

Use your epinephrine (epi-pen) if you carry one, or ask the person with symptoms if they have an epinephrine auto-injector (also called EpiPen, EpiPen Jr, Twinject). Use the epi-pen right away. Epinephrine is a fast-acting drug that reverses airway constriction and restores blood pressure. But the effects are only temporary. Still seek emergency medical care even if your symptoms improve.

By Louis Neipris, MD, Staff Writer
Created on 11/09/2009
Updated on 11/11/2009
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  • Kemp SF. Anaphylaxis and Serum Sickness. In: Rakel RE, Bope ET, eds. Rakel: Conn¿s Current Therapy 2009, 1st ed. Philadelphia, PA: Saunders-Elsevier; 2008.
  • American Academy of Allergy, Asthma and Immunology. What is anaphylaxis?
  • National Jewish Health. Anaphylaxis: Overview.
  • Asthma and Allergy Foundation of America. Anaphylaxis
  • Reddy S. Latex Allergy. American Family Physician. 1998; 57(1)
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