Page 10 - Anaphylaxis in Schools & Other Settings, 3rd Edition Revised
P. 10
Understanding Anaphylaxis What is anaphylaxis?
Anaphylaxis (pronounced anna-fill-axis) is a serious allergic reaction that is rapid in onset and may cause death.1 An allergen is a substance capable of causing an allergic reaction. Upon first exposure in individuals who are predisposed to allergy, the immune system treats the allergen as something to be rejected rather than tolerated. This process is called sensitization. Re-exposure to the same allergen in the now-sensitized individual may result in an allergic reaction which, in its most severe form, is called anaphylaxis.
How common is it?
While the exact prevalence is unknown, it has been estimated that up to 2% of Canadians are at risk of anaphylaxis from food and insect allergy.2 This currently represents about 700,000 Canadians.
What are the signs and symptoms?
Signs and symptoms of a severe allergic reaction can occur within minutes of exposure to an allergen. In rarer cases, the time frame can vary up to several hours after exposure. The ways these symptoms occur can vary from person to person and even from episode to episode in the same person.
Symptoms of anaphylaxis generally include two or more of the following body systems: skin, respiratory, gastrointestinal and/or cardiovascular. However, low blood pressure alone (i.e. cardiovascular system), in the absence of other symptoms, can also represent anaphylaxis.1,3
Skin: hives, swelling (face, lips, tongue), itching, warmth, redness
Respiratory (breathing): coughing, wheezing, shortness of breath, chest pain or tightness, throat tightness, hoarse voice, nasal congestion or hay fever-like symptoms (runny, itchy nose and watery eyes, sneezing), trouble swallowing
Gastrointestinal (stomach): nausea, pain or cramps, vomiting, diarrhea
Cardiovascular (heart): paler than normal skin colour/blue colour, weak pulse, passing out,
dizziness or lightheadedness, shock
Other: anxiety, sense of doom (the feeling that something bad is about to happen), headache, uterine cramps, metallic taste
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Anaphylaxis in Schools & Other Settings
© 2005-2016 Canadian Society of Allergy and Clinical Immunology
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