Anaphylactic Reaction: What You Need To Know

Anaphylaxis can be incredibly frightening both for bystanders, but especially for those suffering directly. Everything can happen so fast. Knowing what to look out for and what to do can genuinely save a life. An anaphylactic reaction (sometimes called anaphylactic shock) is a severe, potentially life-threatening allergic reaction that needs immediate emergency action.

This guide explains the symptoms of anaphylaxis, early warning signs, what can cause anaphylaxis, what to do (including what to do if there’s no EpiPen), and why follow-up care matters more than you may at first think.

What Is An Anaphylactic Reaction?

Anaphylaxis is a severe allergic reaction where the immune system overreacts to an allergen and releases chemicals that can affect the whole body. It often develops within minutes of being in contact with the allergen, but in some cases can occur hours later.

It’s always a medical emergency, no matter the severity of reaction.

Early Signs of Anaphylaxis

Early signs of anaphylaxis can look different from person to person, but common early clues include:

• A sudden, widespread itchy rash or raised red welts (hives)
• Swelling around the face, lips, mouth or eyes
• Feeling light-headed, dizzy, or faint
• A “tight” throat sensation or trouble swallowing
• Breathing changes such as wheezing

Important: symptoms can escalate quickly. If you suspect anaphylaxis, treat it as an emergency.

Symptoms of Anaphylaxis

Symptoms of anaphylaxis typically involve one or more body systems. These can include:

Airway and breathing symptoms

• Swelling of the tongue, mouth, or throat (can cause breathing and swallowing difficulty)
• Wheezing, coughing, noisy breathing, shortness of breath

Circulation symptoms

• Feeling faint, light-headed or collapsing
• Loss of consciousness (in severe cases)

Skin and gut symptoms

• Itchy skin or a raised red rash (hives)
• Swelling of lips, eyes, face, hands, or feet
• Abdominal pain, nausea, vomiting

If you’re ever in doubt, it’s safer to act as though it is anaphylaxis.

Life-Threatening Symptoms of Anaphylaxis

Call emergency services immediately if there are signs of airway or circulation compromise, such as:

• Throat or tongue swelling
• Difficulty breathing or wheezing
• Severe dizziness or faintness
• Collapse or unconsciousness

What Can Cause Anaphylaxis?

There can be many causes of anaphylaxis, but some of the most widely reported triggers include:

• Insect stings (especially wasps and bees)
• Foods allergies (commonly peanuts and tree nuts, but also milk, seafood, eggs, fish, and shellfish)
• Medicines, including certain antibiotics
• Latex (more rarely)

Sometimes, no clear trigger is found. This is known as idiopathic anaphylaxis.

What to Do in An Anaphylactic Emergency

1. Use adrenaline immediately if available

If the person has an adrenaline auto-injector such as an EpiPen, use it straight away. Inject into the outer thigh muscle and follow the device instructions.

2. Call emergency services

Call 999 for an ambulance immediately, even if the person appears to improve after using adrenaline.

3. Position the person safely

• Lie the person flat and raise their legs if possible to support blood circulation.
• If they are struggling to breathe, sitting them upright may help breathing.
• Do not allow them to stand or walk.
• If they become unconscious but are breathing, place them in the recovery position.

4. Give a second dose if needed

If symptoms have not improved after around five minutes, a second adrenaline injection may be needed if another auto-injector is available.

5. Hospital observation is important

Even if symptoms improve, medical observation is recommended because symptoms can return.

What to Do if There is No EpiPen

If adrenaline is not available:

• Call 999 immediately
• Keep the person in the safest position for breathing and circulation
• Stay with them and monitor breathing and consciousness

Antihistamines may help mild allergy symptoms but they do not treat anaphylaxis and should never replace emergency care.

Biphasic Reaction in Anaphylaxis

In some cases, a second wave of symptoms can occur hours after the initial reaction. This is known as a biphasic reaction.

Because of this possibility, people who experience anaphylaxis are usually monitored in hospital after treatment to ensure symptoms do not return.

Preventing Future Reactions

If someone has experienced anaphylaxis, they will usually be referred to a specialist for further assessment.

Trying to prevent a reaction in the first place is one of the most effective methods of managing anaphylaxis. Prevention strategies often include:

• Identifying and avoiding known triggers
• Carrying two in-date adrenaline auto-injectors at all times
• Having an allergy action plan
• Ensuring family, friends, teachers, or colleagues know how to respond in an emergency (e.g. being trained how to administer a EpiPen).

Understanding triggers and recognising symptoms early can significantly reduce the risk of serious complications.

Allergies vs Food Intolerances

It is important to understand that anaphylaxis is caused by allergies, not food intolerances.

Food allergies involve an immune system response and can lead to severe or life-threatening reactions. Food intolerances, on the other hand, typically involve the digestive system and tend to cause symptoms such as bloating, discomfort, or fatigue.

If you suspect a food allergy, medical advice is essential. Accurate diagnosis and an appropriate management plan are critical for safety.

Keeping Safe

Anaphylaxis is rare, but when it happens, fast action is essential. Recognising the early signs, knowing the symptoms, and understanding how to respond can make all the difference in an emergency.

If you or someone close to you is at risk of severe allergic reactions, learning how to use an adrenaline auto-injector and having a clear action plan in place can provide reassurance and protection.

Contact YorkTest For Food Allergy and Intolerance

If you suspect you have a food allergy or intolerance, why not order one of our tests today.