Anaphylaxis Unveiled: Understanding the Severe Allergic Reaction

According to official government statistics, from 1998 to 2018, 101,891 people were hospitalised for anaphylaxis in the UK, with 30,700 cases attributed to food allergies. The most substantial rise in hospital admissions occurred among children under 15 years of age. For adults, anaphylaxis-related hospital admissions increased from 3,751 in 2019 to 4,756 in 2020. The number of adults admitted to hospitals due to allergies has more than doubled since 2013.

Some scientists feel that there is a lack of accurate and reliable data concerning food allergies and anaphylaxis, suggesting potential under-reporting of reactions and deaths which are linked to food allergies.

Defining anaphylaxis

Anaphylaxis occurs when your body experiences a severe and life-threatening reaction to something which you are allergic to. Allergies involve your immune system responding to a typically harmless substance, known as an allergen. While the immune system’s usual role is to protect the body against bacteria and viruses, in cases of allergies, it mistakenly perceives the allergen as a threat and reacts to it. The severity of allergies can range from mild to severe, with symptoms varying from mild irritation to potentially life-threatening conditions.

Anaphylaxis can come on very quickly, highlighting the importance of knowing how to respond in an emergency. Immediate medical attention is crucial, as anaphylaxis prompts the immune system to release an excess of chemicals, leading to serious symptoms and the potential for the person to experience anaphylactic shock. This involves a sudden drop in blood pressure and the narrowing of the airways, making breathing difficult or impossible. Without urgent treatment, anaphylactic shock can pose serious complications and, in some instances, can be fatal.

Anaphylaxis highlights the need for awareness raising with an emphasis on knowing what to do in an emergency situation.

Allergy UK offer a helpful factsheet about anaphylaxis.

Causes and triggers

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 a 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.

Recognising symptoms

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.
• Feeling tired or experiencing confusion.
• Skin that feels cold to the touch.
• Blue, grey or pale lips or face.
• A drop in blood pressure.
• Becoming unconscious.

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

• Call an ambulance immediately.
• Administer an adrenaline auto-injector, if 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.

Anaphylaxis needs to be treated in a hospital straight away. Treatment may include oxygen, adrenaline given by an injection or drip into your vein and fluids given by a drip into your vein.

Anaphylaxis management

There are some important things to think about when it comes to avoiding allergens, including:

• Reading food labels properly – 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.
• Being aware 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.
• Being 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.
• Communicating with restaurants and other food outlets about food allergies before you visit and again when you arrive at the food establishment.
• Being aware of safe meal planning and preparation.
• Choosing fresh food where possible as processed, pre-packaged foods are more likely to contain additives and allergens.
• Being aware of where to source alternative ingredients and snack foods.

Allergen avoidance and preparedness

If you have experienced anaphylaxis, it’s important to communicate this to family and friends and anyone else you are in contact with. This will ensure that everyone is aware of the severity of the situation and how they should respond. Discussing the symptoms of anaphylaxis with the relevant people is an important step. You should discuss your specific allergy and your specific early symptoms. 

You should consider: 

• Educating them about your common triggers.
• Ensuring that they understand the early symptoms.
• Ensuring they understand how quickly symptoms can progress.
• Stressing the urgency of treatment and calling for help.

As anaphylaxis is a severe, potentially life-threatening allergic reaction that requires immediate medical attention, it is important to have an emergency plan in place and for your family, friends and colleagues to be part of creating this plan. An emergency plan should include:

• Identifying the allergen – ensure that everyone understands what your allergies are and how serious each one is.
• Education is key – ensure that your family, friends or colleagues are educated about the specific allergen and understand the symptoms of anaphylaxis.
• Ensure that people are aware of where your medication is kept and how to use it.
• Develop a written emergency action plan.
• Practise the emergency plan with family, colleagues and friends.
• Keep people that you have regular contact with up to date with any changes to your medical situation.

In an emergency situation, an epinephrine auto-injector, also known as an EpiPen, could be life-saving. An epinephrine auto-injector is a medical device designed to deliver a measured dose of the hormone epinephrine, also known as adrenaline. The device is portable and easy to use, making it ideal for an emergency situation. It usually comes as a pen-like device with a needle that automatically injects a predetermined dose of epinephrine when it is used. It works by helping to reverse the symptoms of anaphylaxis by constricting blood vessels, relaxing the muscles in the airways, and improving the blood flow to vital organs. It is therefore vital that your friends and family members understand its purpose and feel confident using it. You should start by:

• Explaining its purpose.
• Showing them the EpiPen and the different parts of it.
• Showing them how to remove the safety cap.
• Demonstrating how to hold it.
• Showing them how to position the EpiPen.
• Explaining 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.
• Explaining they should hold the pen in place for 10 seconds while the dose is delivered.
• Explaining they should then remove the EpiPen and massage the area, as this will help the medication to be absorbed.
• Explaining they should seek emergency help, whether or not the symptoms have improved.
• Allowing them to practise and become familiar with a trainer pen.

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

Living with anaphylaxis

Living with anaphylaxis can be challenging, but with proper management, education and precautions, people with severe allergies can lead fulfilling lives while minimising the risk of severe allergic reactions. It is crucial to work closely with healthcare professionals in order to develop a personalised management plan based on your specific needs and circumstances.

Some important things you can do include:

• Identify your triggers – knowing what your specific triggers are can help you and those around you to avoid those triggers. Be vigilant about reading food labels and asking about ingredients when eating out. Be cautious when trying new foods.
• Carry epinephrine with you at all times – you should carry two adrenaline auto-injectors with you at all times. Learn how to use the auto-injector and teach close friends, family or colleagues as well. Ensure your medication has not expired and that people can access it easily in an emergency situation.
• Have regular check-ups with your healthcare provider – arrange regular check-ups if possible with your allergist in order to monitor your condition and discuss any concerns you have or changes in your symptoms.
• Wear medical alert ID – wear a medical alert bracelet or necklace that clearly states your allergies and the need for epinephrine. This can be crucial in case you are unable to communicate during an emergency situation.
• Take precautions when travelling away from home – be extra cautious when travelling, especially in cases where you may be exposed to new allergens. Carry extra medication, and research local medical facilities at your travel destination ahead of time.
• Develop an emergency action plan – develop an emergency action plan with your healthcare provider and regularly review this. Ensure that those around you are familiar with the plan and know what steps to take in case of an emergency situation.
• Stay informed – stay informed about any advancements in allergy research and treatment options. Attend support groups or connect with others who have similar conditions in order to share experiences and support each other.
• Communicate and advocate for yourself – communicate with the people in your life about what you need in order to manage your allergies and keep yourself safe.

People who have experienced anaphylaxis or who are at risk of anaphylaxis can find this emotionally and psychologically challenging. This may be due to:

• Fear and anxiety – people who have experienced anaphylaxis may develop a heightened fear of future episodes, leading to anxiety and hypervigilance about potential triggers. This can affect their quality of life and enjoyment of day-to-day activities.
• Quality of life – the constant fear of anaphylaxis may affect a person’s ability to engage in everyday activities, leading to a decreased quality of life.
• Social isolation – some people may withdraw from social activities or avoid certain places and events due to fear of allergen exposure.
• Generalised anxiety disorder (GAD) – the risk of developing generalised anxiety disorder may increase due to the unpredictability of anaphylactic reactions. This is when you are worrying constantly and cannot control feeling worried.
• Health anxiety – health anxiety involves intense anxiety and worry about your health, usually to the point that it produces significant distress or interferes with your day-to-day functioning.
• Post-Traumatic Stress Disorder (PTSD) – severe anaphylactic reactions can be traumatic, leading to symptoms of PTSD, including flashbacks, nightmares and emotional distress.
• Chronic stress – the chronic stress associated with living with the constant threat of anaphylaxis may contribute to the development or exacerbation of depression.
• Social relationships – friends and family may not fully understand the seriousness of anaphylaxis.
• Denial or avoidance – some people may deny the severity of their condition or avoid dealing with it, which can lead to inadequate preparedness.
• Workplace challenges – people at risk of anaphylaxis may face challenges in the workplace, such as dealing with colleagues’ lack of understanding or other safety issues.
• School environment – children may encounter difficulties in the school environment if staff are not trained adequately or if there is not enough awareness in the school environment overall.
• Access to resources – ensuring access to mental health resources, such as counselling and support groups, is crucial for people who are dealing with the psychological impact of anaphylaxis.

Anaphylaxis UK offer information, resources and support for anyone affected by anaphylaxis.