Anaphylaxis (pronounced ana-fil-ax-is) is a life threatening severe allergic reaction. It can occur when someone with allergies is exposed to something they are allergic to (known as an allergen). Reactions usually begin within minutes and rapidly progress but can occur up to 2-3 hours later.
It is a medical emergency, and requires immediate treatment.
In most allergic reactions the resulting chemicals are released locally into the tissues in a particular part of the body (skin, eyes etc.). This means the symptoms of the allergic reaction usually only occur in this area.
In anaphylaxis, the chemicals that cause the allergic symptoms (e.g. histamine) are released into the bloodstream. The symptoms of anaphylaxis usually occur within minutes of exposure to the trigger substance (allergen) but sometimes an hour or so late
In some cases, there’s no obvious trigger. This is known as idiopathic anaphylaxis.
A reaction is usually classed as anaphylaxis if there are changes in a person’s breathing, heart rate or blood pressure.
Any one or more of the following symptoms may be present. These are often referred to as the ABC symptoms.
Swelling in the throat, tongue or upper airways (tightening of the throat, hoarse voice, difficulty swallowing)
Sudden onset wheezing, breathing difficulty, noisy breathing
Dizziness, feeling faint, sudden sleepiness, tiredness, confusion, pale clammy skin, loss of consciousness
Dial 999 and inform the controller that the patient is suffering from anaphylaxis.
Here are the steps you need to follow if someone is having an anaphylactic shock:
If your child has asthma or has been prescribed a salbutamol inhaler and your child is wheezy, please consider giving up to 10 puffs of salbutamol using spacer device after the adrenaline pen. Remember - in suspected anaphylaxis, always give adrenaline pen first followed by other treatments.
If you are suffering from an anaphylactic shock, you should use your adrenaline pen immediately. While waiting for the ambulance, it is better if you lie down as this helps to maintain your blood pressure and avoids injury if you faint. You may be more comfortable with your shoulders raised a bit if you feel wheezy or short of breath.
If you have a serious allergy or have experienced anaphylaxis before, it’s important to try to prevent future episodes.
The following can help reduce your risk:
Finding out if you’re allergic to anything that could trigger anaphylaxis can help you avoid these triggers in the future.
If you’ve had anaphylaxis and have not already been diagnosed with an allergy, you should be referred to an allergy clinic for tests to identify any triggers.
The most commonly used tests are:
If a trigger has been identified, you’ll need to take steps to avoid it in the future whenever possible.
You can reduce the chances of being exposed to a food allergen by:
You can reduce your risk of being stung by an insect by taking basic precautions, such as:
Some specialist allergy centres can also offer special treatment to help desensitise you to insect stings (immunotherapy).
If you’re allergic to certain types of medicines, there are normally alternatives that can be safely used.
For example, if you’re allergic to:
Always tell any healthcare professional about medicine allergies you have, as they may not be aware of them.
You may be prescribed an adrenaline auto-injector if there’s an ongoing risk you could develop anaphylaxis.
There are three types of auto-injectors – EpiPen, Jext and Emerade – that are each slightly different. Instructions are also included on the side of each injector if you forget how to use it or someone else needs to give you the injection.