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Anaphylaxis

Anaphylaxis - Severe Allergic Reaction

Anaphylaxis is a life threatening allergic reaction that requires immediate medical treatment. About 1 in 1333 people in England have experienced anaphylaxis and around 20 people die each year in the UK because of it. 

How does Anaphylaxis occur?

Anaphylaxis occurs when the body’s immune response to an allergen runs out of control. This has effects on all parts of the body. Common allergens that trigger such a reaction are food products (such as nuts or shellfish), bee or wasp venom, latex, or medications, although sometimes no trigger for the episode can be identified. 

What happens in anaphylaxis is that smallest blood vessels in the body – the capillaries - become ‘leaky’ and fluid leaks out from the blood and fills up the soft tissues of the body. This means two things, first is that those soft tissues swell up, and second is that the blood pressure drops because so much fluid has left the blood which effectively makes the arteries ‘emptier’. This drop in blood pressure means that not enough blood reaches the vital organs and the brain which can ultimately result in death. This is described as anaphylactic shock.

What are the symptoms to look out for?

lady suffering from Anaphylaxis

Early symptoms of anaphylaxis include:


  1. A hoarse voice and wheeze as the tissues around the airways swell causing those airways to narrow. 
  2. Swelling of the tongue and lips, and a florid nettle-type rash can spread over the body. 
  3. The sufferer will feel their heart begin to race as it frantically tries to pump blood to the vital organs, and they will start to feel faint or lightheaded.
  4. Traditionally, people suffering from anaphylaxis are described as experiencing a feeling of ‘impending doom’
  5. The breathing rate increases, the sufferer may become confused due to lack of oxygen in the brain, and they may also experience gastrointestinal symptoms like vomiting or abdominal pain.

Who is most likely to suffer from Anaphylaxis?

Anaphylaxis is most likely to happen in people who have pre-existing allergies or have other conditions linked to allergy such as asthma or eczema, but it can happen in anyone.

What to do if someone is experiencing Anaphylaxis

People who have experienced anaphylaxis previously are usually encouraged to carry an adrenaline autoinjector with them. This is a pen-like device that is used to inject a dose of adrenaline into the person if they start to experience any symptoms of anaphylaxis. This device is commonly called an ‘EpiPen’ but other brands include Emerade and Jext. The person can either inject themselves if they feel symptoms coming on, or a bystander can do the injection for them if they know how to. The devices are easy to use and are absolutely lifesaving. There are lots of training videos for each brand on YouTube and it is worthwhile looking at these so you know what to do should you need to. 

dialing 999 on mobile phone

Adrenaline is the immediate treatment for anaphylaxis and there should be no delay in delivering the adrenaline if anaphylaxis is suspected. If adrenaline is given, or anaphylaxis occurs in someone who does not carry an autoinjector, then it is essential to call 999. The ambulance will respond to anaphylaxis as the most serious category of medical emergency regardless of whether adrenaline has already been given. Sometimes people will require multiple adrenaline injections and someone who has experienced anaphylaxis is always taken to hospital for further treatment (usually in the form of steroid medication) and a period of monitoring.

If you are with someone who appears to be suffering from anaphylaxis, other than calling for help immediately, you should try to remove the source of any potential allergen e.g. removing any latex products they are still in contact with or wiping any food products away from their mouth. If you are trained to do so, be prepared to perform CPR should the person go into cardiac arrest. 

How best to avoid Anaphylaxis

Sometimes the cause of an Anaphylaxis episode is obvious and the mainstay of treatment is simply avoiding the trigger and carrying an adrenaline pen in case of accidental exposure. 


Sufferers usually also undergo allergy testing in the form of blood tests. This can confirm the suspected allergy and may also reveal other potential triggers as some people who are allergic to one thing may also have other allergies. 


For example, someone with a peanut allergy may have allergies to other nuts and, interestingly, people with latex allergies are often also allergic to bananas, strawberries and kiwi fruit, amongst others. 

Sometimes the cause of an episode is obvious and the mainstay of treatment is simply avoiding the trigger and carrying an adrenaline pen in case of accidental exposure. Sufferers usually also undergo allergy testing in the form of blood tests. This can confirm the suspected allergy and may also reveal other potential triggers as some people who are allergic to one thing may also have other allergies. For example, someone with a peanut allergy may have allergies to other nuts and, interestingly, people with latex allergies are often also allergic to bananas, strawberries and kiwi fruit, amongst others. 

In Summary

Anaphylaxis is a very frightening experience but, with prompt action, it can be effectively treated. The most important action to take is to call 999 and make sure you, or the person you are with, gets immediate medical help. 

Allergy testing available from One Day Tests

The best way to start your allergy diagnosis and treatment journey is with a comprehensive allergy blood test.


The Ultimate Allergy Screening Blood Test covers an impressive 99% of all the potential type 1 allergen sources and just requires a simple blood sample. 


The 295 allergens covered in the test include; Tree Pollen, Grass Pollen, Mould, Insect Venom & Food. 


View the full list of allergens covered in the test here.


About One Day Tests: We offer a wide range of blood tests that enable you and understand your health like never before. Whether it’s for routine health checks, or you have symptoms you would checking, our range of blood tests provides the  convenience, accuracy, and peace of mind you deserve.


No waiting times for appointments, choice of home test kits or local clinic appointments, and receive rapid results. One Day Tests is your number one choice for blood testing.


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