Anaphylaxis is a severe and potentially life-threatening reaction to a trigger such as an allergy.
It's also known as anaphylactic shock.
Symptoms of anaphylaxis
Anaphylaxis usually develops suddenly and gets worse very quickly.
The symptoms include:
- feeling lightheaded or faint ↗
- breathing difficulties ↗ – such as fast, shallow breathing
- a fast heartbeat
- clammy skin
- confusion ↗ and anxiety
- collapsing or losing consciousness
What to do if someone has anaphylaxis
Anaphylaxis is a medical emergency. It can be very serious if not treated quickly.
If someone has symptoms of anaphylaxis, you should:
- use an adrenaline auto-injector if the person has one – but make sure you know how to use it correctly first
- call 999 for an ambulance immediately (even if they start to feel better) – mention that you think the person has anaphylaxis
- remove any trigger if possible – for example, carefully remove any wasp or bee sting stuck in the skin
- lie the person down flat – unless they're unconscious, pregnant or having breathing difficulties
- give another injection after 5-15 minutes if the symptoms don't improve and a second auto-injector is available
If you're having an anaphylactic reaction, you can follow these steps yourself if you feel able to.
Read about how to treat anaphylaxis ↗ for more advice about using auto-injectors and correct positioning.
Triggers of anaphylaxis
Anaphylaxis is the result of the immune system – the body's natural defence system – overreacting to a trigger.
This is often something you're allergic to, but isn't always.
Common anaphylaxis triggers include:
- foods – including nuts, milk, fish, shellfish, eggs and some fruits
- medicines – including some antibiotics ↗ and non-steroidal anti-inflammatory drugs (NSAIDs) ↗ such as aspirin ↗
- insect stings ↗ – particularly wasp and bee stings
- general anaesthetic ↗
- contrast agents – special dyes used in some medical tests to help certain areas of your body show up better on scans
- latex – a type of rubber found in some rubber gloves and condoms
In some cases, there's no obvious trigger. This is known as idiopathic anaphylaxis.
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:
- identify any triggers – you may be referred to an allergy clinic for allergy tests ↗ to check for anything that could trigger anaphylaxis
- avoid triggers whenever possible – for example, you should be careful when food shopping or eating out if you have a food allergy ↗
- carry your adrenaline auto-injector at all times (if you have two, carry them both) – give yourself an injection whenever you think you may be experiencing anaphylaxis, even if you're not completely sure
Read more about how to prevent anaphylaxis ↗.