Anaphylaxis and Exercise: Precautions and Management

Anaphylaxis is a severe and life-threatening allergic reaction that requires immediate medical attention when it occurs. Traditionally, we associate anaphylaxis with serious allergies to foods such as nuts or insect bites (such as wasp or bee stings). 

Many people may not realise that physical activity, such as exercise, can in fact contribute to a person suffering anaphylaxis. This usually happens when exercise is combined with additional triggers (these can be food or non-food related triggers). 

When exercise is identified as a contributing factor to a person suffering from anaphylaxis it is referred to as exercise-induced anaphylaxis, or EIA. 

Anaphylaxis triggers during exercise

We may think of exercise as an intense cardio session; however, on occasion people have been known to experience anaphylaxis whilst doing more gentle activities such as gardening or jogging. Whilst EIA is considered a rare condition, the consequences of anaphylaxis can be fatal, therefore it is important to try to identify and limit contact with any possible triggers and know what to do if anaphylaxis occurs.

A combination of factors causes EIA, so for a person to experience exercise-induced anaphylaxis they need to encounter an allergic trigger (food or non-food) in addition to physical exercise. This combination can cause chemicals, including histamine, to be released in the body and this leads to anaphylaxis.

The chemical histamine is responsible for many of the common symptoms of allergic reaction such as swelling or itching. During anaphylaxis, the immune system overreacts to allergens, releasing large amounts of histamine plus other chemicals into the bloodstream. 

Up to half of cases of anaphylaxis relating to exercise are food related, with a variety of foods cited as the trigger. These include:

• Shellfish
• Fish
• Nuts
• Wheat
• Eggs
• Milk
• Various fruits
• Alcohol

In some cases, for anaphylaxis to occur, patients have needed to ingest a combination of the trigger food(s) followed by exercising, in order to have a reaction. 

Non-food-related triggers may include:

• Medication (including non-steroidal anti-inflammatory drugs)
• Extreme temperatures (both cold and warm)
• Pollen
• Dust mites
• Hormonal changes
• Infections

In most patients, the triggers alone are often benign. It is the combination of the trigger(s) plus exercise that causes problems. This means that people who suffer from exercise-induced anaphylaxis are sometimes completely unaware that a particular allergen poses an issue to them and have no history of allergic reactions, until EIA occurs.

Symptoms of anaphylaxis

The signs and symptoms of anaphylaxis will often appear suddenly and the reaction can get worse quickly. This means it is important to recognise anaphylaxis and get treatment as soon as possible.

Exercise-induced anaphylaxis may include the following symptoms:

• Swelling of the throat and tongue
• Breathing difficulties, coughing and/or wheezing
• Rapid breathing
• Tiredness, dizziness or loss of consciousness
• Confusion and panic
• Problems with speaking or swallowing, hoarseness
• Sensation of the throat constricting or feeling blocked
• Changes in skin colour (skin, lips or tongue have greyish or blueish tinge – in people with a darker complexion this is more apparent on the soles of the feet or palms)
• Skin feels cold to the touch
• Skin rash that feels itchy and raised (hives)
• Cramps
• Stomach upset / nausea

These reactions are sometimes grouped as A, B, C symptoms, which stands for:

• AIRWAY
• BREATHING
• CIRCULATION

In exercise-induced anaphylaxis, any of the A, B, C symptoms may be present, or a combination of them. Medically, an allergic reaction is usually considered anaphylaxis if the symptoms have a severe effect on breathing, heart rate or blood pressure. 

Precautions before exercise

Research into exercise-induced anaphylaxis is ongoing, with current statistics estimating that around 30-50% of EIA instances are food dependent. This means that they only occur when a specific trigger food is introduced in combination with exercise. 

If you have any concerns about your health or wellbeing, consult with your GP to discuss this. If you have suffered anaphylaxis, you may be referred for allergy testing. 

If your GP is considering sending you for treatment or investigations, such as allergy testing, you may need to:

• Keep a food diary
• Change or switch around what you eat
• Consider alternatives
• Make and attend medical appointments
• Understand your medical history and answer questions about your diet, general health and lifestyle

It is vital that if you have allergies, you understand them and how they affect you and take precautions to mitigate risk, such as avoiding triggers, checking labels on food packaging and understanding cross-contamination.

Research is currently ongoing into EIA, with some scientists considering whether taking antihistamines prior to exercising can help protect those with allergies suffering from anaphylaxis. Additionally, researchers are unsure whether EIA can go away on its own or is a lifelong issue. However, as reactions can be life-threatening it is always best to approach with caution. 

If you have suffered from EIA, assume that there is a chance it may reoccur and take precautions to manage it safely. There is no reason to stop exercising or stop living a healthy lifestyle; in fact, staying active is key for our health and wellbeing. Rather than avoiding exercise, you can take sensible steps to prevent and manage allergic reactions or instances of anaphylaxis in the future, plus learn what to do if a severe reaction does happen one day. 

Managing anaphylaxis during exercise

In the early stages of exercise-induced anaphylaxis, the simplest tool to use to address the situation is to stop and rest. This may be all you need to stop the reaction from progressing. Remain calm and listen to what your body is telling you. 

If symptoms are not under control or worsen, this means a person is now experiencing anaphylaxis, which can get worse suddenly. To mitigate the symptoms, you can use an autoinjector to administer life-saving adrenaline, if one is available. 

Adrenaline helps to relieve low blood pressure by narrowing blood vessels. It also helps to open up airways and relieve breathing difficulties.

Autoinjectors or an epinephrine autoinjector (EpiPen) are a form of hypodermic device that contains adrenaline. They are used to quickly and effectively deliver medicine to treat allergy-related emergencies. 

They are straightforward and simple to use:

• Remove the safety cap from the injector
• Place it firmly against the thigh at a right angle
• A ‘click’ sound means that adrenaline release has been activated
• Keep it in place for 10 seconds
• Make sure the patient is lying down and does not get up or walk around, even if they start to improve
• Use a second adrenaline shot if no improvement is made within 5 minutes

An autoinjector can be used in the thigh area through clothing, providing that the needle is able to penetrate the skin.

A person experiencing anaphylaxis may require further first aid procedures after receiving their adrenaline shot such as being put in the recovery position or being given CPR; providing you know how to do this safely you can do this whilst waiting for an ambulance to arrive.   

You should check the expiry dates on your autoinjectors regularly and replace them before they expire. Your GP can arrange this. They need to be kept away from extreme temperatures, so don’t leave them out in the sun or in the fridge. 

Hospital treatments available for anaphylaxis

When a person suffers anaphylaxis and emergency services are called, paramedics will arrive and provide treatment and assessment. When you have had an attack of anaphylaxis you can expect to be taken to the hospital and will usually be kept in. This is because, on occasion, people appear to initially recover but may suffer a second bout known as biphasic anaphylaxis. This may happen 1 to 72 hours after the initial onset of symptoms (but usually within the next 10 hours). 

In the hospital, treatments for anaphylaxis include:

• Adrenaline (given via injection or drip)
• Oxygen
• Fluids via intravenous drip

After anaphylaxis, expect to stay in the hospital for several hours or overnight for observation. 

You may be given adrenaline autoinjectors before you leave hospital. If so, you will be provided with two. Keep at least one with you all the time, especially when you go out to exercise, and make sure you know how to administer them safely. Inform anyone else who may need to know such as close friends, your teachers or workplace.

Strategies for exercising safely with allergies

Many people in the UK live with allergies. If you have suffered from an occurrence of EIA, or have allergies that affect your health, you can still keep up your exercise routine by making smart decisions and practising self-care. 

• Know your allergen triggers and make sensible choices around routes, locations, snacks and drinks
• If you feel anaphylaxis coming on, stop exercising and rest immediately
• If you know you are prone to anaphylaxis or have experienced it in the past, try not to exercise in remote or unpopulated locations
• Consider exercising with a friend or exercise buddy. Make them aware of your medical history and tell them how to administer your autoinjector
• Listen to what your body is telling you and don’t try to push yourself too hard
• Keep medications (including your adrenaline autoinjector such as EpiPen) and charged mobile phone with you whilst exercising
• Be mindful of your triggers and avoid or mitigate them as far as possible
• Consider a medical alert bracelet to alert others to severe allergies or conditions
• Take care with what you eat or drink before an exercise session; it is recommended to wait a minimum of 4-6 hours after eating a trigger food before you exercise
• If you encounter problems with a certain type of exercise, consider switching to a different type, such as something less vigorous
• Stay hydrated
• Take special precautions if you have asthma and always keep your inhaler with you when exercising
• Put your safety first, even if this means rearranging an exercise session or waiting until the weather or temperature changes
• Take regular breaks and avoid exercise if you are unwell or taking certain medication, such as antibiotics

To keep yourself and others safe, the key points to remember about EIA are:

Anaphylactic reactions induced by exercise are rare, although they are extremely serious and require immediate medical attention. This usually includes adrenaline being administered to the patient. 

Exercise-induced anaphylaxis only occurs once a person is exposed to a trigger (or combination of triggers) plus physical activity. 

The reaction could be a one-time only occurrence or something that reoccurs and it is important to consult with medical staff to investigate further and take any necessary medication. If you are provided with an autoinjector keep at least one (preferably two in case a single dose isn’t enough) with you at all times. Let those around you know of your condition and prioritise your own safety and wellbeing.