Anaphylaxis adrenaline autoinjector use
Informed by recognized medical guidance
Overview
Anaphylaxis is a severe, life-threatening allergic reaction that can happen quickly after you are exposed to something you are allergic to, such as certain foods, insect stings, or medications. An adrenaline autoinjector is a device you use to give yourself a shot of adrenaline (also called epinephrine) during such a reaction. It can help stop the reaction and save your life.
Key facts
- Anaphylaxis can be fatal if not treated quickly.
- An adrenaline autoinjector is the first-line treatment for anaphylaxis.
- You should use your autoinjector at the first sign of a severe allergic reaction.
Anaphylaxis is not common, but it can happen to anyone who has allergies. It is estimated that 1 in 50 people in the UK may experience anaphylaxis at some point.
Anyone with a known allergy can experience anaphylaxis. It is more common in children and young adults, but it can occur at any age.
Symptoms
- Difficulty breathing or noisy breathing
- Swelling of the throat or tongue
- A feeling of choking or tightness in the throat
- Loss of consciousness or fainting
- Severe dizziness or feeling about to collapse
- ⚠If you have used your adrenaline autoinjector, always call for emergency help immediately after. Even if you feel better, you still need medical assessment.
- ⚠If you experience a less severe allergic reaction but have a history of anaphylaxis, seek medical advice promptly.
Common symptoms
- Trouble breathing or wheezing
- Swelling of the lips, tongue, or throat
- Hives or widespread red, itchy skin rash
- Nausea, vomiting, or diarrhea
- Dizziness or feeling faint
- A sudden drop in blood pressure (feeling very weak)
Symptoms in children
- In children, symptoms may also include a hoarse voice, coughing, or noisy breathing
- They might become upset, clingy, or irritable
- Some children describe a feeling of 'impending doom'
Symptoms in older adults
- Older adults may have symptoms similar to others, but they may also have underlying heart or lung conditions that make anaphylaxis more dangerous
- They might experience severe confusion or collapse
Causes
Main causes
- Foods like peanuts, tree nuts, milk, eggs, fish, shellfish, and sesame
- Insect stings from wasps or bees
- Medications such as antibiotics or painkillers
- Latex (rubber gloves, balloons)
Risk factors
- Having a known allergy that has caused anaphylaxis before
- Having asthma, especially if not well-controlled
- Being allergic to multiple things
- Not carrying your adrenaline autoinjector when needed
When to see a doctor
See a doctor urgently if:
- If you use your adrenaline autoinjector for anaphylaxis, you must go to the emergency room immediately after. You need monitoring for at least a few hours.
- If you have symptoms of anaphylaxis but no autoinjector, call emergency services right away.
Book a routine appointment if:
- If you have had an allergic reaction that was not severe, but you are worried it could happen again, make a routine appointment with your GP or an allergy specialist.
- If you are prescribed an adrenaline autoinjector, learn how to use it and practice with a trainer pen.
Diagnosis
Anaphylaxis is usually diagnosed based on your symptoms and the history of exposure to an allergen. Your doctor may also do tests to confirm what you are allergic to.
Tests that may be done
- Skin prick test: a tiny amount of the suspected allergen is placed on your skin to see if you react
- Blood test: measures the level of allergy antibodies (IgE) in your blood
- Oral food challenge: under medical supervision, you eat small amounts of the suspected food to see if you react
What to expect at your appointment
If you are diagnosed with anaphylaxis, you will be prescribed an adrenaline autoinjector and taught how to use it. You may also be referred to an allergy specialist for further management.
Treatment
The main treatment for anaphylaxis is adrenaline given through an autoinjector into your outer thigh. It works quickly to reverse the allergic reaction. After using it, you must always call emergency services even if you feel better.
Self-care at home
- Always carry your adrenaline autoinjector with you – two if possible
- Avoid known triggers by reading food labels, telling restaurants about your allergies, and avoiding insect nests
- Wear a medical alert bracelet or carry an allergy card mentioning your allergy and autoinjector
Medical treatments
In the hospital, doctors may give you additional medications to control symptoms, such as antihistamines for itching and hives, and steroids to prevent a delayed reaction. They will also monitor your breathing, blood pressure, and heart rate. If needed, you may receive oxygen or fluids through a drip.
Living with this condition
Living with a risk of anaphylaxis means being prepared at all times. You need to avoid your allergens, carry your autoinjector, and know how to use it. You also need to make sure your family, friends, and colleagues know what to do in an emergency.
Lifestyle tips
- Carry two adrenaline autoinjectors in a labelled case
- Avoid eating foods that may contain your allergens when out
- Tell your workplace or school about your allergy and where your autoinjectors are kept
- Consider an allergy action plan from your doctor
Diet and exercise
If your allergy is food-related, you must follow a strict avoidance diet. Read ingredient labels carefully. Discuss with a dietitian if you need help planning meals. Exercise can also trigger anaphylaxis in some people, especially after eating foods you are allergic to, so be aware of this.
Mental health and emotional wellbeing
Living with the fear of a severe allergic reaction can cause anxiety, stress, and worry. It is normal to feel this way. You may want to talk to a counselor or join a support group to share experiences. If you feel overwhelmed, reach out to your doctor or a mental health helpline for support.
Prevention
Anaphylaxis itself cannot always be prevented, but the risk can be reduced by avoiding known allergens and always having your autoinjector with you. Allergy shots (immunotherapy) may help some people become less sensitive to certain allergens like insect stings.
Complications
If left untreated
- Severe difficulty breathing can lead to a lack of oxygen and damage to organs
- A sudden drop in blood pressure can cause shock and loss of consciousness
- Death can occur within minutes if adrenaline is not given
Long-term outlook
With prompt use of an adrenaline autoinjector and emergency medical care, the outlook for anaphylaxis is very good. Most people recover fully without long-term problems. It is important to be prepared and follow your allergy action plan.
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Always verify with your doctor
Health guidelines vary by country and region. The information in this article is based on international clinical guidelines but may not reflect the specific guidelines, medications, or practices in your country. Always discuss your health concerns with your own doctor or healthcare provider, and refer to your local national health guidelines where available.
Important notice This information is for educational purposes only. It does not replace professional medical advice, diagnosis, or treatment. Always consult a qualified healthcare provider about your specific situation. If you are experiencing a medical emergency, call your local emergency services immediately.
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Sources and guidance
This article is educational and is prepared with reference to recognized health information and clinical guidance sources where available. Specific source links may vary by topic.
Last updated: July 21, 2026
Educational note: This information is for education only and is not a diagnosis.
Use it to support, not replace, advice from a licensed clinician.
If symptoms are severe, worsening, or urgent, call your local emergency number or seek emergency care.