Anaphylaxis

Anaphylaxis is the most dramatic expression of allergy. In an anaphylactic attack, symptoms may develop within minutes after coming into contact with the allergen and may rapidly become very severe, threatening vital body functions such as respiration and blood circulation.

Most anaphylactic attacks are triggered by food allergens, insect venoms, drugs and latex.

In a number of cases, the cause of the anaphylactic reaction remains obscure (idiopathic anaphylaxis).

Symptoms

The initial symptoms of an anaphylactic attack can be flushing, a sensation of warmth, redness or itchiness of the skin, urticaria which very often involves the whole body, nausea, vomiting or abdominal cramps.

Sometimes an anaphylactic attack can stop here. However, sometimes these symptoms are followed very quickly by more severe and truly dangerous ones:

• In some people, swelling of lining of the mouth, throat or larynx can cause problems with respiration. When the swelling is very severe it can even lead to asphyxia.
• Some people develop asthma attacks. Sometimes during these attacks there is such a marked narrowing of the bronchi that breathing becomes impossible.
• The substances released from the immune cells during an anaphylactic attack cause an enlargement of the blood vessels in the whole body. This causes a drop in the blood pressure which is usually felt as palpitations (caused when the heart increases its rate and force of beating to compensate for the fall in blood pressure and maintain the blood flow), sensation of light head or dizziness. If the blood vessels are very much enlarged (vascular collapse) even a great increase in heart rate cannot keep the blood pressure up to an acceptable minimum level. As a consequence, blood flow to the organs falls dramatically and they no longer receive enough oxygen. The person becomes more dizzy and confused and finally will become unconscious.

Anyone who has had an anaphylactic reaction should consult an allergy specialist without delay in order to find out what caused the reaction and what measures must be taken to prevent or to treat a future attack.

The effects of epinephrine become visible very quickly (seconds to minutes) after injection. However, sometimes the anaphylaxis symptoms disappear quickly but they come back again after a few minutes. If this happens you must inject another dose of epinephrine and seek urgent medical help.

Remember to ask the doctor for a new prescription for an epinephrine auto-injector to replace your emergency kit and, if possible, buy it as soon as you get out of the hospital.

Various measures can be taken to prevent the development of a new anaphylactic attack. These measures differ depending of the cause of the attack. Your doctor will certainly tell you more about this but if you need more information try the following web-sites: www.theucbinstituteofallergy.com  or www.anaphylaxis.org.uk or contact your local allergy organization.

Children at risk of anaphylaxis should have a written action plan with necessary medication available in a labelled box at school/nursery/ child minder. All those who care for them need training in how and when to use the adrenaline.