Boots WebMD Partners in Health
Return To Boots

Allergies health centre

Select a topic to explore more.
Select An Article


Anaphylaxis is a serious, potentially life-threatening allergic reaction characterised by swelling of the mouth and throat, hives, and a feeling of impending doom. In severe cases difficulty breathing and a sudden drop in blood pressure causes shock. If anaphylactic shock isn't treated immediately, it can be fatal.

This condition occurs when the immune system creates specific disease-fighting antibodies (called immunoglobulin E or IgE) toward a substance that is normally harmless, such as food. When you are first exposed to the substance, your body does not react, but it does produce the antibodies. When you are exposed to the substance again, the antibodies spring into action, releasing large amounts of a protein called histamine. Histamine causes the symptoms described above.

What are the symptoms of anaphylaxis?

Anaphylaxis may begin with severe itching of the eyes or face and, within minutes, progress to more serious symptoms. These symptoms include swallowing and breathing difficulties, abdominal pain, cramps, vomiting, diarrhoea, urticarial (hives), and angioedema (swelling similar to urticaria, but the swelling is beneath the skin instead of on the surface).

If you have symptoms of anaphylaxis, seek emergency medical attention immediately. The condition can quickly result in an increased heart rate, sudden weakness, a drop in blood pressure, shock, and, ultimately, unconsciousness and death.

What are the common triggers of anaphylaxis

Food is generally the most common cause of anaphylaxis. Common food triggers include nuts, shellfish (shrimp, lobster), dairy products, egg whites, and sesame seeds. Wasp or bee stings are also common causes of anaphylaxis.

Additionally, exercise can trigger anaphylaxis if the activity occurs on its own or after eating allergy-provoking food.

Pollens and other inhaled allergens ( allergy-causing substances) rarely cause anaphylaxis.

Some substances can cause anaphylactic reactions. Common ones are fish, latex, and some medications, such as penicillin.

How is anaphylaxis diagnosed?

Anaphylaxis is diagnosed based on its symptoms. People with a history of allergic reactions may be at greater risk of developing a severe reaction in the future.

Skin testing may help confirm the substances that cause severe allergic reactions. However, this type of test may not be recommended if you have reason to suspect that you will have an anaphylactic reaction to the test substance.

How is anaphylaxis treated?

There is only one effective treatment for anaphylaxis - adrenaline by injection, which rapidly reverses anaphylactic symptoms. It is typically given through an automatic injection device. The most common injection site is the thigh.

If you are near someone who is going into anaphylactic shock, call for professional medical help immediately. Cardio-pulmonary resuscitation and other lifesaving measures may be required.

In addition to adrenaline, treatment for shock may include intravenous fluids and drugs that support the actions of the heart and circulatory system. After a person in shock is stabilised, antihistamines and steroids may be given to further reduce symptoms.

How can I be prepared?

If you are allergic to bee stings or any other substances that cause anaphylaxis, you should always be prepared. Ask your doctor to prescribe you adrenaline injection kits and carry these with you at all times.

Also, it's important that you inform doctors and other medical staff of any drug allergies or other allergies before undergoing any type of medical treatment, including dental care.

It is also a good idea to wear a MedicAlert bracelet or pendant, or carry a card that identifies your allergy. In cases of emergency, it could save your life.

Next Article:

WebMD Medical Reference

Medically Reviewed by Dr Rob Hicks on November 07, 2016

Allergy & asthma newsletter

Get tips for breathing easier.
Sign Up

Popular slideshows & tools on BootsWebMD

woman coughing
Home remedies for coughing
smiling baby
Causes and remedies
bowl of soup
Small changes that lead to weight loss
mother and child
Caring for a baby with cows' milk allergy
woman holding mouth
What causes sensitive teeth?
smiling woman
Do you know how to get a beautiful smile?
bain illustration
Best foods for your brain
woman doing situps
7 most effective exercises
avacado on whole wheat crackers
Plenty to choose from
egg in cup
Surprising things that can harm your liver