Anaphylaxis

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

• Exercise;
• Anesthetics, and;
• Latex.

Unknown causes

Sometimes, despite in-depth investigations, the trigger cannot be found in some people.

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.

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.

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.

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.

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.