Anaphylaxis

Anaphylaxis (also known as anaphylactic shock) is an allergic condition that can be severe and potentially fatal.

Anaphylaxis is your body's immune system reacting badly to a substance (an allergen), such as food, which it wrongly perceives as a threat.

The whole body can be affected, usually within minutes of contact with an allergen, though sometimes the reaction can happen hours later.

What are the symptoms?

The reaction is unpredictable and varies from mild itchiness and swelling to severe and life-threatening symptoms. 

If you have a severe anaphylactic reaction, you will experience a sudden drop in blood pressure and narrowing of the airways, which causes breathing difficulties and wheezing.

You will usually experience sudden swelling around the eyes, lips, genitals, hands, feet and other areas.

For a full list of symptoms, see the Symptoms section, above.

What triggers anaphylaxis?

Anaphylaxis can be triggered by a wide range of foods and other substances. The most common food triggers include nuts, sesame seeds, shellfish and eggs.

Sometimes a person can be so sensitive to a particular food that they can develop anaphylaxis just by breathing in particles from it, such as dust from nuts.

Anaphylaxis can also be caused by an allergic reaction to wasp or bee stings, natural latex (rubber) and certain drugs, such as the antibiotic penicillin. See Causes, above, for more information.

Can it be prevented?

If you have had an anaphylactic reaction, doctors will perform some tests to find out what you are allergic to. Once you know the trigger, you can take steps to avoid it.

If you have a food allergy, be vigilant and check food labels for ingredients. If you are at a restaurant or buying takeaway food, ask if your food contains the allergen. A dietitian can advise you on how to exclude the allergen from your diet.