Management of Anaphylaxis

Anaphylaxis is a medical emergency, and prompt action is crucial. Researchers argue that there is a lack of precise and dependable data on food allergies and anaphylaxis, suggesting potential under-reporting of related reactions and fatalities. 

Hospital admissions for anaphylactic shock in adults increased from 3,751 to 4,756 from 2019 to 2020. The number of adult patients who were admitted to hospital because of allergies has more than doubled since 2013, reaching a record high of 27,172 in 2019/2020.

We can’t say for certain why allergy rates are increasing; however, researchers have some theories. One theory is that improved hygiene is to blame, as children are not getting as many infections, therefore with fewer parasites to fight, the immune system perceives a threat against things that should be harmless. Other theories are vitamin D deficiency, changes in diet including eating more processed foods, environmental factors and increased awareness and diagnosis.

What is anaphylaxis?

Anaphylaxis happens when your body has a serious, life-threatening reaction to something you are allergic to. An allergy is your immune system responding to a substance that is usually harmless. The immune system’s job is to defend your body against things such as bacteria and viruses. However, in the case of allergies, your immune system mistakenly identifies a substance, known as an allergen, as being harmful to you and reacts to it. Allergies can vary in severity from mild to severe, and the symptoms can range from being slightly irritating to being life-threatening. 

Anaphylaxis can come on very quickly, so it is important to know what to do in an emergency situation. It requires immediate medical attention. Anaphylaxis can cause the immune system to release an excess of chemicals which can cause serious symptoms and result in the person going into shock. This is known as anaphylactic shock. It is where there is a sudden drop in blood pressure and there is a narrowing of the airways which can block your breathing. If left untreated, anaphylaxis can develop into anaphylactic shock and result in serious complications or even death.

Anaphylaxis is typically triggered by exposure to an allergen, which is a substance that the immune system identifies as harmful even though it is generally harmless to most people.

What are the causes of anaphylaxis?

Anaphylaxis is a severe and potentially life-threatening allergic reaction that can occur extremely rapidly after exposure to an allergen. The immune system plays a central role in anaphylaxis. 

Anaphylaxis is caused by:

• Allergen exposure – anaphylaxis is triggered by exposure to an allergen, which is a substance that the immune system identifies as being harmful, although it may be completely harmless to most people.
• There is then an immune system response – when someone with a predisposition to allergies is exposed to an allergen, their immune system produces antibodies specific to that allergen.
• Sensitisation – in people who have been sensitised to a particular allergen through prior exposure, the antibodies attach to mast cells.
• Re-exposure – when re-exposed to the allergen, antibodies become bound to the cells.
• Release of chemicals – this binding triggers the release of various chemicals, including histamine.
• Symptoms of an allergic reaction – the released chemicals cause reactions throughout the body, which can lead to widespread inflammation and various symptoms affecting the skin, respiratory system, cardiovascular system, and gastrointestinal system. This can lead to difficulty breathing, swelling of the face and throat, a drop in blood pressure, a rapid or weak pulse, hives, nausea, and in severe cases, loss of consciousness.

Anaphylaxis often occurs rapidly, which means that within minutes to an hour after exposure to the allergen the person can become extremely unwell.

What are the main triggers of an anaphylactic reaction?

It is important to note that the severity of a reaction and specific triggers can vary from person to person.

Common allergens that are known to cause anaphylaxis include:

• Food allergens – the most common food allergens include peanuts, almonds, walnuts, cashew nuts, shellfish, fish, milk, eggs, soy and wheat.
• Insect stings or bites – the most common are bee stings, wasp stings, mosquitos, bedbugs, hornets, fire ants, ticks and fleas.
• Medication – common medications are antibiotics, anti-inflammatory drugs, aspirin and certain vaccines.
• Latex – this is a form of rubber found in products like balloons, gloves and some medical equipment.
• Exercise-induced – some people may experience anaphylaxis during or after exercise, especially after the consumption of certain foods which could have triggered the reaction.
• Immunotherapy – although rare, allergy shots can lead to anaphylaxis.
• Environmental allergens – pollen, mould, pet dander and other environmental allergens. These are usually associated with milder allergic reactions but in some rare cases, they can trigger anaphylaxis.
• Idiopathic anaphylaxis – this means that the cause is unknown or unidentifiable despite there being thorough investigation. In idiopathic anaphylaxis, people can experience severe allergic reactions, including symptoms like difficulty breathing, swelling, and a drop in blood pressure, but the trigger remains unknown. This can be particularly difficult to manage in terms of future prevention.

Who is at risk?

There are certain risk factors for someone experiencing anaphylaxis. These include:

• Experiencing anaphylaxis before – if you have already experienced anaphylaxis, this makes it more likely that you will experience it again in the future. Future episodes may also be more severe.
• A family history of anaphylaxis – having a close family member who has experienced anaphylaxis makes it more likely that you will experience it again.
• Having allergies – having allergies makes it more likely that you will experience anaphylaxis.
• Your age – children and young adults may be at a higher risk of anaphylaxis, though it can occur at any age.
• Having asthma – the combination of asthma and anaphylaxis can lead to more serious respiratory symptoms.
• Having multiple allergen sensitivities – people with multiple allergies may be at an increased risk of anaphylaxis.
• A delay in administering an adrenaline auto-injector – there should be no delay in giving this if anaphylaxis is suspected. It is recommended that anyone at risk of anaphylaxis carries two EpiPens with them at all times.

Young people between 16 and 24 years old are the group recognised as being most at risk of anaphylaxis as they become more independent from their parents and are more likely to experiment with new, unfamiliar foods, they are more likely to travel alone or with friends and may be reluctant to carry two EpiPens with them at all times which is necessary when you have a serious allergy.

What to do in an emergency

Symptoms of anaphylaxis happen very quickly and include:

• Swelling of the throat and tongue.
• Difficulty breathing or breathing very fast.
• Wheezing, coughing or noisy breathing.
• Difficulty swallowing or tightness in the throat.
• Feeling faint, dizzy or fainting.
• Becoming unconscious.
• Feeling tired or experiencing confusion.
• Skin that feels cold to the touch.
• Blue, grey or pale lips or face.
• A drop in blood pressure.

If you suspect someone is experiencing anaphylaxis, you should follow these steps:

• Call an ambulance immediately.
• Administer an adrenaline auto-injector, if this is available. This is sometimes called an EpiPen. You should use it as directed, which usually involves injecting the person into the outer thigh and holding it in place for 10 seconds.
• If their symptoms have not improved after 5 minutes, use a second adrenaline auto-injector.
• Lie the person down and elevate their legs.
• Stay with the person and monitor their breathing.
• Do not offer any food or drinks as this could potentially make their condition worse.
• Do not ask the person to stand or walk at any time, even if they feel better.
• If the person has been stung by an insect, try to remove the sting if it’s still in the skin.
• Administer CPR if the person has stopped breathing or their heart has stopped.

Managing anaphylaxis

There are some important things you can do to protect yourself when it comes to avoiding allergens, including:

• Read food labels thoroughly – food manufacturers are required to list common allergens, such as milk, eggs, peanuts, tree nuts, soy, wheat, fish and shellfish. You should also educate family and friends about always reading food labels carefully. For more information about what should be on a food label, please see our knowledge base.
• Be mindful of hidden ingredients – you should familiarise yourself with alternative names for common allergens. Some foods may contain hidden allergens in the form of additives, flavourings or colourings.
• Be aware of cross-contamination – you should also educate friends and family about this. They should know to avoid using shared utensils, cutting boards and kitchen equipment that may have been in contact with allergens.
• Create safe environments and avoid your triggers – ensure your living and work environments are as allergen-free as possible. Communicate your needs to those around you and work together in order to create a safe space.
• Communicate with restaurants and other food outlets about food allergies before you visit and again when you arrive at the food establishment.
• Be aware of safe meal planning and preparation.
• Choose fresh food where possible as processed, pre-packaged foods are more likely to contain additives and allergens.
• Be aware of where to source alternative ingredients and snack food.

Living with anaphylaxis requires careful management and preparation on a daily basis in order to keep yourself safe. Some helpful tips for doing this include:

• Understand your triggers – work with your healthcare provider in order to identify and understand your specific allergens or triggers. Keep a detailed record of your reactions, including potential triggers, symptoms and severity of your symptoms.
• Emergency action plan – develop and regularly review an emergency action plan. This plan should include detailed instructions on what to do in the event of an allergic reaction. Share your action plan with others so that they are aware of what to do in case of an emergency.
• Carry epinephrine – always carry an epinephrine auto-injector prescribed by your healthcare provider. Ensure that you and those around you know how to use the auto-injector correctly. You should also check the expiration date regularly and replace it before it expires.
• Wear medical ID – wear a medical identification bracelet or necklace that indicates your severe allergy and includes emergency contact information. This will help first responders and medical professionals understand your condition and will enable them to act quickly in case you are unable to communicate.
• Educate others – educate family, friends and colleagues about anaphylaxis and how to respond in case of an emergency.
• Regular check-ups – have regular check-ups with your healthcare provider in order to monitor your condition and discuss any changes in your symptoms.

Treatment for anaphylaxis

If you are at risk of anaphylaxis, preventative measures are vital and are the most effective way to prioritise your health. 

In the event of someone experiencing anaphylaxis you should call 999 immediately. 

You should administer epinephrine if this is available. The administration of an epinephrine auto-injector, often referred to as an EpiPen, can be life-saving. The medical device is specifically designed to administer a controlled amount of the hormone epinephrine, also known as adrenaline. It is made to be small, portable and user-friendly. An EpiPen has a needle that automatically dispenses a predetermined epinephrine dosage when used. It works by reversing anaphylaxis symptoms by narrowing blood vessels, relaxing airway muscles, and enhancing the blood flow to essential organs. 

It can also be useful for your friends and family members to understand its purpose and feel confident using it in case of an emergency. It may help to:

• Explain its purpose.
• Show them the EpiPen and the different parts of it.
• Show them how to remove the safety cap.
• Demonstrate how to hold it.
• Show them how to position the EpiPen.
• Explain how to inject the EpiPen. Explain to them that they should inject the EpiPen firmly into the thigh until it clicks. The click indicates that the injection has started.
• They should hold the pen in place for 10 seconds while the dose is delivered.
• They should then remove the EpiPen and massage the area, this will help the medication to be absorbed.
• They should seek emergency help, whether or not the symptoms have improved.
• You could allow them to practise and become familiar with a trainer pen.

Let them know that the instructions are included on the side of the injector in case they forget how to use it.

You should stay with the person at all times and try to keep them calm. Reassure them and encourage them to lie down. Monitor their vital signs such as breathing, pulse and blood pressure. Be prepared to perform CPR if necessary. CPR is a life-saving medical procedure which is given to someone who is in cardiac arrest. It helps to pump blood around their body when their heart is unable to do this.

The British Heart Foundation offers an online CPR course. It is recommended that everyone knows CPR in the event of an emergency situation – it could save a life.