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Anaphylaxis

Anaphylaxis is a severe, potentially fatal allergic reaction.  This article provides an overview of the causes of anaphylaxis, its symptoms, and how it is treated.  For more specific information, please contact your physician.

During anaphylaxis, allergic symptoms can affect several areas of the body and may threaten breathing and blood circulation.   Food allergy is the most common cause of anaphylaxis, although allergies to insect stings, medications, or latex are other potential triggers.  Rarely, anaphylaxis is triggered by exercise.  Another uncommon form of anaphylaxis occurs when a person eats a problem food and exercises soon thereafter.  Sometimes anaphylaxis occurs without an identifiable trigger, but this is also very rare. 

Although anyone who has a food allergy can experience anaphylaxis, the foods most likely to cause a severe reaction are peanuts, tree nuts, fish and shellfish.  People who have both asthma and a food allergy are at greater risk for anaphylaxis.   

At present, strict avoidance of problem foods is the only way to prevent anaphylaxis, although researchers are working on preventive therapies. 

Epinephrine (adrenaline) is a medication that can reverse the severe symptoms of anaphylaxis.  It is given as a “shot” and is available as a self-injector that can be carried and used if needed.   Epinephrine is a highly effective medication, but it must be administered promptly during anaphylaxis to be most effective.  Even if epinephrine is administered promptly and symptoms seem to subside completely, patients should always be taken to the emergency room for further evaluation and treatment.  

Symptoms of Anaphylaxis
Anaphylaxis often begins within minutes after a person eats a problem food.  Less commonly, symptoms may begin hours later.  About 25% of patients have a second wave of symptoms one to several hours after their initial symptoms have subsided.  This is called biphasic anaphylaxis.  

The symptoms of anaphylaxis can range from mild to severe and life-threatening.  Mild symptoms include one or more of the following:

• Nasal congestion
• Runny nose
• Slight cough
• Nausea
• Vomiting
• Diarrhea
• Stomach pain
• Itchy mouth/ear canal
• Lip swelling (Note: If this becomes obstructive, it is a serious symptom)
• Odd taste in mouth
• Flushing/redness
• Itching
• Hives
• Swelling
• Eczema
• Uterine contractions

Any one of the following symptoms is a sign of a dangerous reaction that requires immediate medical attention:

• Obstructive swelling of the lips, tongue, and/or throat
• Trouble swallowing
• Shortness of breath or wheezing
• Turning blue
• Drop in blood pressure  (feeling faint, confused, weak, passing out)
• Losing consciousness
• Chest pain
• Weak pulse
• Sense of “impending doom”

Anaphylactic shock occurs when a patient’s blood pressure drops to a dangerously low level. 

Coping with Anaphylaxis
The unpredictability of anaphylaxis is one of the most distressing aspects of living with a food allergy.  A person who previously had only mild reactions can have a life-threatening reaction, while someone with a history of anaphylaxis may experience a mild reaction.  If you have a food allergy or an anaphylactic reaction, it is important that you consult with an allergist.  The allergist will review your medical history and discuss allergen avoidance and appropriate treatments for both anaphylaxis and milder allergic reactions.  (For tips on avoiding problem foods, please check out the Food Allergy Quick Reference on the right side of this page.) If you are taking medications for other conditions, your allergist will determine whether or not they could interfere with the activity of epinephrine and suggest other options.

Everyone who has a food allergy should know how to respond to a severe reaction.  If your allergist prescribes epinephrine, you may be concerned about learning to use the autoinjector.  With proper instruction and practice, however, you will soon become proficient.  Knowing that you can take care of yourself or a loved one in an emergency will give you peace of mind.  Depending on which type of autoinjector your doctor prescribes, you can find detailed instructions and resources online (EpiPen or Twinject).  Keep in mind that epinephrine expires after a certain period, so be sure to check the expiration date and renew your prescription in time.  Although you may never need to take your medication, it’s important to have it available and ready for use at all times.  (Allergists generally recommend that if you have an anaphylactic reaction and your epinephrine has expired, you should take the medication anyway and, as always, call 911 for help immediately.)

Fortunately, thanks to the effectiveness of epinephrine and a growing awareness of the seriousness of food allergies, deaths from anaphylaxis are not common, and many past fatalities were preventable.  Those at highest risk for fatal reactions appear to be teenagers or young adults who also have asthma and who delay in receiving epinephrine. It cannot be stressed too often that anaphylaxis should always be handled as a medical emergency. 

To recap, be sure to:

• Learn all you can about avoiding allergens. Read food labels carefully and don’t hesitate to ask questions when eating away from home. Vigilance is your first line of defense against anaphylaxis. 
• Have your medication with you wherever you go.
• Talk to your allergist about when and how to use emergency medications.
• Make sure prescriptions are up-to-date.
• Wear medical alert identification jewelry at all times.
• Don’t delay using your epinephrine while waiting to see if your symptoms improve!  Use your emergency medications as prescribed. 
• Epinephrine is not a “foolproof” treatment.  Don’t take chances by eating a problem food.
• Get to an emergency room for evaluation and further treatment right away—even if your medication has stopped the reaction.
• Make sure you’ll be safe if a second wave of symptoms begins.  Stay in the emergency room for at least four hours.

Remember: These steps save lives, even in the most serious cases.   Stay safe by making these guidelines part of your day-to-day life—and get on with the business of living!