Anaphylaxis
What is anaphylaxis?
Anaphylaxis, also known as anaphylactic shock, is a very severe form of allergic reaction. Immediate and life-threatening symptoms, including breathing difficulties, can be the result of exposure to a trigger. Anaphylaxis is a serious but treatable medical condition.
Causes
When a foreign substance enters your body, your immune system mounts a defense by producing antibodies. Anaphylaxis occurs when your immune system overreacts to a trigger that would normally be harmless. When this occurs, a chemical chain reaction leads to severe allergy symptoms. These triggers are known as allergens and can include:
Food
Nearly any food can trigger a food allergy that can develop into an anaphylactic shock. Foods that commonly trigger anaphylaxis include:
- Crustaceans (e.g., lobsters, shrimp and crabs);
- Nuts (e.g., peanuts, cashews, walnuts, pecans and almonds);
- Eggs;
- Fish;
- Soy products;
- Sesame products, and;
- Milk.
Insect venom
- Bees;
- Wasps;
- Ants, and;
- Ticks.
Medications
- Some prescription medications (e.g., penicillin);
- Some over-the-counter medications (e.g., aspirin), and;
- Herbal preparations.
Rare causes
Unknown causes
Sometimes, despite in-depth investigations, the trigger cannot be found in some people.
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Allergens
An environmental substance that, although not harmful in itself, elicits a vigorous reaction from the immune system.
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Anesthetics
A medication or other substance that causes a temporary loss of sensations, including pain.
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Antibodies
A protein molecule produced by the immune system. Antibodies bind specifically to foreign substances to neutralize them or target them for destruction.
Risk factors
Some risk factors associated with anaphylaxis may include:
History of anaphylaxis
If you have a personal history of experiencing anaphylaxis, you are at risk of having the allergic reaction again. These subsequent allergic reactions can be more serious than the first reaction. If there is a family history of anaphylaxis to a certain allergen, there is a higher risk of you developing anaphylaxis to this trigger.
Previous conditions
If you already have previous allergies, asthma or eczema, you have an increased risk of anaphylaxis.
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Allergic reactions
A problematic physiological response to an allergen that comes into contact with the body.
Signs and symptoms
The symptoms of anaphylaxis may occur within minutes of being exposed to an allergen, with 20 minutes being the average amount of time for symptoms to appear. Some signs and symptoms can include:
- Swelling of the face (e.g., the lips or eyelids);
- Skin reactions (e.g. reddening of the skin, or hives);
- Swollen tongue;
- Swollen throat;
- Tightening of the airways;
- Hoarseness in the voice or an inability to talk;
- Wheezing or coughing;
- Nausea, vomiting or diarrhea;
- Reduction in blood pressure;
- Dizziness, fainting or unconsciousness, and;
- Paleness and floppiness in children.
Symptoms of anaphylaxis can be swollen lips and eyelids, and skin reddening.
Methods for diagnosis
To diagnose anaphylaxis or to identify an allergen that is affecting you, some tests can include:
- Evaluation of medical history;
- Examination of signs and symptoms during anaphylaxis;
- Blood tests (e.g., for certain antibodies), and;
- Skin prick tests to rule out or confirm suspected triggers.
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Antibodies
A protein molecule produced by the immune system. Antibodies bind specifically to foreign substances to neutralize them or target them for destruction.
Types of treatment
Treatment of anaphylaxis can include:
First aid
As anaphylaxis is a very serious medical emergency, it is important that you call an ambulance immediately (000) and follow the medical personnel's instructions. If you have an adrenaline auto-injector (see below) and have been trained in how to use it, it is best to administer this first.
Adrenaline injection
This involves an injection of adrenaline, usually into the muscle of your outer thigh, to treat the reaction.
Adrenaline auto-injector
Once your doctor identifies that you are at risk of anaphylaxis, they will prescribe you adrenaline. This comes as an auto-injectable device, commonly known as Epipen®, which is designed to deliver a precise dose of adrenaline to treat anaphylaxis. There are different dosage levels for children and adults.
An adrenaline auto-injector is used to treat anaphylaxis.
Allergy specialist
To help determine the specific cause of your anaphylaxis, your doctor may refer you to see an allergy specialist. They can help you create an anaphylaxis management plan.
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Adrenaline
A substance secreted primarily by the adrenal glands that helps to prepare the body for exertion. It is involved in regulating blood pressure, heart rate and breathing. Adrenaline can also be used as a drug to treat a number of conditions, including cardiac arrest and anaphylaxis.
Potential complications
When severe anaphylactic shock occurs, life-threatening conditions can arise. These complications can include stopping of breathing or heart contractions. In this case, you will require cardiopulmonary resuscitation (CPR) and other emergency treatment immediately.
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CPR
An emergency lifesaving procedure that involves manually pumping air into the lungs, and compressing the chest to circulate the blood. This first aid technique is used when someone's breathing or heartbeat has stopped.
Prognosis
In some cases, children will grow out of their allergies. If you have been diagnosed with anaphylaxis caused by a certain allergen, you may be able to avoid the trigger and not experience anaphylaxis. However, it is important to carry an adrenaline auto-injector just in case you are exposed to an allergen that causes anaphylaxis.
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Adrenaline
A substance secreted primarily by the adrenal glands that helps to prepare the body for exertion. It is involved in regulating blood pressure, heart rate and breathing. Adrenaline can also be used as a drug to treat a number of conditions, including cardiac arrest and anaphylaxis.
Prevention
In order to help prevent anaphylaxis, a management plan can be created. Some suggestions to consider include:
- Avoiding triggers that are known to cause anaphylaxis;
- Notifying your work colleagues and friends of your allergies and how they can help treat you in an emergency, and;
- Wearing a medical bracelet that will alert ambulance officers to your condition, if you become unconscious.
References
- Allergy & Anaphylaxis Australia. Accessed July 14 2014. link here
- Anaphylaxis. Better Health Channel. Accessed July 14 2014. link here
- Anaphylaxis Definition - Diseases and Conditions - Mayo Clinic. Accessed July 14 2014. link here
10 Most frequently asked questions (FAQs)
Anaphylaxis, also known as anaphylactic shock, is the most severe form of allergic reaction. Immediate and life-threatening symptoms, including breathing difficulties, can be the result of exposure to an allergen (trigger). Without prompt medical attention, anaphylaxis can cause death. What are the symptoms of anaphylaxis? The symptoms of anaphylaxis can occur almost immediately after exposure to an allergen. Anaphylaxis can occur within minutes: 20 minutes is the average amount of time for symptoms to appear. Symptoms can include: • Facial swelling, including swelling of the lips and eyelids; • Skin reactions (e.g. reddening of skin across the body or hives); • Swollen tongue; • Swollen throat; • Constriction of the airways; • Inability to talk, or a hoarse voice; • Wheezing or coughing; • Nausea, vomiting or diarrhea; • A drop in blood pressure; • Dizziness, fainting or unconsciousness, and; • Paleness and floppiness in young children. Anaphylaxis occurs when your immune system overreacts to a trigger that would be harmless for most people. Common triggers include: certain foods (e.g., nuts, shellfish), insect venom (e.g., bees or wasps) and some medications (e.g., penicillin or aspirin). Less common causes of anaphylaxis include exercise, anesthesia and latex. Sometimes, even after extensive testing, the cause of anaphylaxis cannot be found. Anaphylaxis can affect anyone that has a severe allergy. Sometimes children will grow out of allergies or triggers. How is anaphylaxis diagnosed? Anaphylaxis can be diagnosed using a combination of different tests. These can include a doctor reviewing your medical history, examination of signs and symptoms during anaphylaxis, blood tests (e.g., for the presence of certain antibodies) and skin prick tests of suspected triggers. How is anaphylaxis treated? If you or someone else is experiencing anaphylaxis, it is important to call an ambulance. Treatment involves an injection of adrenaline, usually given into the thigh muscle. If your doctor has identified that you are at risk of anaphylaxis, they will prescribe you injectable adrenaline. This is commonly known as an EpiPen®. You carry it with you at all times, so that you can use it immediately if you get an anaphylactic reaction. Can anaphylaxis be cured? Anaphylaxis cannot be cured. Some children may grow out of one or more of their particular food allergies. Otherwise, avoiding known triggers is the only way to prevent anaphylaxis. Will anaphylaxis clear on its own? No, anaphylaxis is a very serious condition and will rarely clear on its own. It is best to call an ambulance as you will require an injection of adrenaline and sometimes other treatment. What can be done at home to treat anaphylaxis? If your doctor has identified that you are at risk of anaphylaxis, they will prescribe you injectable adrenaline, or adrenaline shots, for you to carry with you at all times so that you can be treated immediately if you have an anaphylactic reaction. After using injectable adrenaline, it is still important to seek urgent medical attention, as further treatment may be needed. Can anaphylaxis be prevented? If you have identified the causes or triggers for your anaphylaxis, you can prevent the condition by avoiding the causes. Sometimes anaphylaxis cannot be prevented; for example, you may not know that you are allergic to a trigger until it causes you to go into anaphylactic shock.
Related topics
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