What is Anaphylaxis?

Anaphylaxis is the most severe form of allergy and can be life threatening.  Typically there is a dramatic, rapid and diverse occurrence of any combination of the following symptoms, all of which are known to be associated with severe allergy:

• Feeling of faintness or unexplained apprehension

• Sensation of irritation and/or restriction in throat 

• Swelling of mouth, lips, tongue

• Itchy rash or tingly swellings anywhere on body

• Difficulty with breathing, talking or swallowing

• Cough and/or wheeze

• Blue lips, loss of consciousness

• Breathing stops, pulse stops, heart stops beating

If severe, an attack may be accompanied by asthma, laryngeal oedema (throat swelling or narrowing), fainting or collapse (blood pressure falls).  A good working definition of anaphylaxis (there is no generally accepted standard definition) is that it should include at least one of the two potentially severe problems; breathing difficulty (due to asthma or throat narrowing) and fall in blood pressure (fainting collapse or loss of consciousness).  Egg, fish, peanut and other tree nuts (such as brazil nut), have been noted for their ability to provoke severe reactions.²⁶⁷  The risk factors for anaphylaxis may include history of a previous severe reaction to a food and a history of asthma especially if poorly controlled.  

Risk Management

It is the advice of the Department of Health in the UK that all patients who have suffered from anaphylaxis should be seen in an allergy clinic.²⁶⁴  People who are regarded as at risk of anaphylaxis (often because they have had a previous attack) should ensure that they have this risk assessed and that an attempt has been made to properly identify the cause.  The need to carry an adrenaline auto-injector (e.g. EpiPen^®) in case of a further attack needs to be assessed, this treatment will not be required in every case.  Where there is a risk that a serious reaction might occur, this treatment will normally be advised.  Where the item responsible for triggering anaphylaxis is clearly known, the ease with which the particular item can be safely avoided needs to be taken into account when assessing the requirement to carry adrenaline.  For example, certain foods are difficult to avoid with total certainty (e.g. nuts), whereas others should be more easily avoided (e.g. lobster).  

Most cases of food-related fatal anaphylaxis occur outside the home and are often associated with a failure to get the sufferer to lie horizontal, if necessary with legs raised.  Delay in the administration of adrenaline is another factor.  Occasionally the triggering of an anaphylactic reaction requires concurrent recent food allergen ingestion together with exercise, although when either stimulus is received alone, no reaction occurs.  This condition is known as food-dependent exercise-associated anaphylaxis.

Not all anaphylaxis is caused by foods.  Drugs, anaesthetics, bees, wasps and rubber latex are known to cause the condition.  In a proportion of cases, no allergic trigger can be identified in spite of extensive investigation.

The incidence of anaphylaxis appears to be increasing.  The number of hospital admissions due to anaphylaxis doubled between 1991 and 1994 and increased seven-fold between 1994 and 2003.²⁶⁵  Whilst this gives evidence of the increase in severe reactions, the figures only cover a proportion of cases of anaphylaxis, not all of which need admission following emergency treatment.

Injectable adrenaline (e.g. EpiPen®)

Not only is failure to carry adrenaline a risk factor for a patient with a severe anaphylaxis risk, so to is failure to use it when the situation requires it.  The EpiPen® device is easy to use, but it is important that those who need it have been shown not only how to use it, but precisely when to use it.  Your GP, practice nurse or allergy clinic can advise.  For a website containing an animated demonstration of how to use the EpiPen click on the box right.

Support Organisations

The Anaphylaxis Campaign
This organisation provides an extremely valuable service to its members both by providing help-line support, an excellent regular newsletter, and the representing the interests of patients with severe food and other allergies in discussions both with politicians and the food industry.  All those who have suffered anaphylaxis or severe laryngeal oedema are advised to become members of this excellent organisation.

The MedicAlert® Foundation
This the only non-profit making, registered charity providing a life-saving identification system for individuals with hidden medical conditions and allergies. This takes the form of body-worn bracelets or necklets bearing the MedicAlert^® symbol on the disc and supported by a 24 hour emergency telephone service. Each member receives an Emblem that is engraved with the wearer’s main medical condition(s) or vital details, a personal ID number and a 24 hour emergency telephone number that can access their details from anywhere in the world in over 100 languages.

Recommended Websites

Anaphylaxis Campaign
A valuable organisation that deals with the concerns and needs of all who suffer from anaphylaxis or laryngeal oedema.  They produce a useful regular newsletter.
www.anaphylaxis.org.uk

Allergic Reactions
The website provides information about severe allergic reactions and the use of the EpiPen.  The device is described in detail and clear instructions concerning its use are provided.
www.allergic-reactions.com

www.allergybadges.co.uk

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