Anaphylaxis is a life-threatening allergic reaction that happens very quickly. It can be caused by food, medicine or insect stings. Call 999 if you think you or someone else is having an anaphylactic reaction.
Symptoms of anaphylaxis happen very quickly.
They usually start within minutes of coming into contact with something you're allergic to, such as a food, medicine or insect sting.
Symptoms include:
You may also have a rash that's swollen, raised or itchy.
You or the person who's unwell may also have a rash that's swollen, raised or itchy.
These can be signs of a serious allergic reaction and may need immediate treatment in hospital.
Follow these steps if you think you or someone you're with is having an anaphylactic reaction:
Do not stand or walk at any time, even if you feel better.
There are different types of adrenaline auto-injectors and each one is given differently.
Anaphylaxis needs to be treated in hospital immediately.
Treatments can include:
You'll usually stay in hospital for around 2 to 12 hours, but you may need to stay longer.
Before you leave hospital, you'll be given 2 adrenaline auto-injectors to keep in case you have another anaphylactic reaction.
An adrenaline auto-injector is a special device for injecting adrenaline yourself. You'll be told how and when to use it.
You may also be referred to an allergy specialist for tests.
There are some things you can do to help prevent anaphylaxis or prepare for if it happens.
avoid the food, medicine or thing that you're allergic to – for example, if you have a food allergy, check food labels carefully and tell staff at restaurants and cafes about your allergy
carry 2 adrenaline auto-injectors with you at all times
check your adrenaline auto-injector expiry dates regularly and get new ones before they expire
practice how to use your adrenaline auto-injector by using a trainer injector (an injector that has no needle or medicine in it) – you can order one online from the company that makes your injector
teach friends, family, colleagues or carers how and when to use your adrenaline auto-injector
use your adrenaline auto-injector if you think you may have anaphylaxis, even if your symptoms are mild
wear medical alert jewellery such as a bracelet with information about your allergy – this tells other people about your allergy in case of an emergency
do not leave your adrenaline auto-injectors anywhere too hot or cold such as in the fridge or outside in the sun
There's more advice about what you can do to avoid common allergies. Find out more about:
Anaphylaxis happens when your body has a serious reaction to something you're allergic to.
Allergies that can sometimes cause anaphylaxis include:
Sometimes it's not known what caused an anaphylactic reaction.