For some people, even a trace amount of allergen can cause a life-threatening reaction.


People with asthma and anaphylaxis seem to have an increased risk of developing a severe reaction.

What is anaphylaxis?

Anaphylaxis is a life-threatening allergic reaction to a specific trigger in a person who has become sensitive to that trigger.

What are common triggers?

The most common food allergens are peanuts, tree nuts, fish, shellfish, eggs, milk, soy, wheat, sesame seeds, and sulphites. Other triggers include insect stings, medication, latex and exercise.

Who is at risk?

A conservative estimate is that 2% of the population (approximately 600,000 Canadians) may be affected by potentially life-threatening allergies. The incidence is higher in children and it has increased dramatically in the last decade.

Why is anaphylaxis so dangerous?

Anaphylactic shock is an explosive overreaction of the body's immune system to a triggering agent (allergen). Many body systems may be involved, upper and lower respiratory, gastrointestinal and cardiovascular. It can cause swelling, difficulty breathing, abdominal cramps, vomiting, diarrhea, circulatory collapse, coma and death.

Symptoms tend to develop quickly although there may also be a delayed onset. Someone who is experiencing a reaction may become uneasy, upset and red in the face. They may also develop a rapid heartbeat, prickling and itchiness in the skin and ears, sneezing, coughing and difficulty breathing. Shock may then follow, in which blood vessels become leaky, blood pressure falls and the person becomes cold, clammy and faint.