Please be aware that this information is provided to supplement the care provided by your physician. It is neither intended nor implied to be a substitute for professional medical advice. CALL YOUR HEALTHCARE PROVIDER IMMEDIATELY IF YOU THINK YOU MAY HAVE A MEDICAL EMERGENCY. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with any questions you may have regarding a medical condition.


Anaphylaxis

(Anaphylactic Reaction; Severe Allergic Reaction)
Pronounced: ANNA-fill-AX-is
Definition

Anaphylaxis is a severe, sometimes life-threatening, allergic reaction. It affects multiple organs, including the heart and lungs.

It is important to seek medical care right away if there are symptoms of anaphylaxis.

Causes

Substances that cause anaphylaxis are often called allergens or triggers. Common triggers include:

  • Blood transfusion
  • Foods and food additives, especially eggs, peanuts, seafood, cow's milk, soy, fish, shellfish, seeds, and tree nuts
  • Insect stings or bites from bees, wasps, hornets, yellow jackets, and fire ants
  • Latex products (eg, gloves, medical tubing, condoms)
  • Medicines (eg, antibiotics, seizure medications, muscle relaxants)
  • Some pain medicines, especially narcotics
  • Vaccines

Some triggers, like dyes used in x-ray procedures, can cause a reaction similar to anaphylaxis.

Risk Factors

These factors increase your chance of developing anaphylaxis. Anyone can have anaphylaxis. Tell your doctor if you have any of these risk factors:

  • Children who have certain conditions, such as spina bifida and urogenital defects may be at increased risk for latex allergy (because of heavy exposure to latex they have during multiple surgeries)
  • History of eczema , hay fever , or asthma
  • Previous allergic reaction to the substances listed above, even if it is a mild reaction
Symptoms

The symptoms of anaphylaxis usually occur within minutes after exposure to an allergen, but can occur hours later. Symptoms may be mild or very severe, including death. They include:

  • Heart arrhythmias
  • Low blood pressure, shock
  • Nausea, vomiting, cramping, diarrhea , or abdominal pain
  • Convulsions
  • Feelings of anxiety
  • Hives and itching
  • Lightheadedness, pale/blue skin color, low pulse, dizziness
  • Obstruction of the nose, mouth, and throat
  • Severe respiratory distress (eg, chest tightness, shortness of breath, wheezing)
  • Swelling, redness, stinging or burning, especially on the face, mouth, eyes, or hands
  • Warmth or redness of skin
Diagnosis

The doctor will suspect anaphylaxis if you have symptoms and have been exposed to a likely allergen. It is also important to follow up with a doctor who specializes in allergies (allergist/immunologist). The diagnosis of allergy with a risk of anaphylactic reactions is made based on the patient’s history. It is confirmed with skin tests and sometimes blood tests done by allergy specialists.

Treatment

Anaphylaxis is a medical emergency that requires immediate medical treatment, including:

  • Bronchodilators—to improve breathing
  • Cardiopulmonary resuscitation (CPR)—may be necessary in severe cases when anaphylaxis leads to cardiovascular collapse. Severe anaphylaxis may require mechanical ventilation until swelling is brought under control.
  • Epinephrine (adrenaline) injection—makes blood vessels constrict, relaxes the airway, stops itching and hives, and relieves gastrointestinal cramping
  • Intravenous fluids—to maintain blood pressure
  • Other medicines—corticosteroids and/or antihistamines may be given after the epinephrine to decrease inflammation and improve breathing.
  • Oxygen

NOTE : If you receive emergency epinephrine, you should go to the emergency room right away, even if your symptoms have gone away.

If you are diagnosed with anaphylaxis, follow your doctor's instructions .

Prevention

Avoiding substances that trigger anaphylaxis is the best prevention. In addition:

  • Your doctor may give you self-injectable epinephrine to keep with you at home, work, in the car, and when you travel. Be sure family and friends know how to use the kit too. Get training from your doctor and practice using it in the doctor's office.
  • Allergy shots can decrease the risk of anaphylaxis and reduce the severity of the reactions to certain triggers.
  • Always remain in the doctor's or dentist's office 30 minutes after receiving an injection. Report any symptoms right away.
  • If allergic to insect stings, wear protective clothing when outside.
  • Make sure the school nurse and teachers know about any allergies your child has. If your child has self-injectable epinephrine, make sure school staff knows how to use it and understands when it is needed.
  • Make sure your epinephrine kit is not expired.
  • Tell your doctor or dentist about your allergies before taking any medicine. When possible, ask that medicines be taken as a pill. Allergic reactions can be more severe with injected medicines.
  • Wear a medical alert jewelry that lists your allergies.

Last reviewed: September 2011 by Michael Wein, MD.

RESOURCES:
CANADIAN RESOURCES:
References:
  • Anaphylaxis. EBSCO DynaMed website. Available at: http://www.ebscohost.com/dynamed/what.php . Updated June 2009. Accessed July 21, 2009.
  • Kay AB. Allergy and allergic diseases–second of two parts. N Engl J Med . 2001;344:109-113.
  • Lieberman P, Kemp SF, Oppenheimer J. The diagnosis and management of anaphylaxis: An updated practice parameter. J Allergy Clin Immunol . 2005 Mar;115(3 Suppl 2):S483-523.
  • National Institute of Allergy and Infectious Diseases website. Available at: http://www3.niaid.nih.gov/ . Accessed March 25, 2007.
  • Pumphrey R. Anaphylaxis: can we tell who is at risk of a fatal reaction?. Curr Opin Allergy Clin Immunol . 2004; 4:285.
  • Sampson, HA, Munoz-Furlong, A, Campbell, RL, et al. Second symposium on the definition and management of anaphylaxis: summary report—Second National Institute of Allergy and Infectious Disease/Food Allergy and Anaphylaxis Network symposium. J Allergy Clin Immunol . 2006;117:391.
  • Simons E. Anaphylaxis. J Allergy Clin Immunol . 2010;125: S161-81.
  • Winbery SL, Lieberman PL. Anaphylaxis. Immunol Allergy Clin North Am 1995;15:447.