- Analysis: Anaphylaxis and Allergy in the Emergency Department
- Data Tables: Anaphylaxis and Allergy in the Emergency Department
September 10, 2015 — Data released today by the Canadian Institute for Health Information (CIHI) shows that while the number of visits to Canadian emergency departments (EDs) for all allergic reactions (including anaphylaxis) remained stable from 2006–2007 to 2013–2014, the number of visits per 100,000i population specifically for anaphylaxis increased by 95%. In the same time frame, there was also a 64% rise in the rate of Canadians dispensed a prescription epinephrine auto-injector, according to CIHI’s National Prescription Drug Utilization Information System Database.
About 1% of all ED visits each year are attributed to allergic reactions (including anaphylaxis). In 2013–2014, this represented more than 85,000 visits in Ontario and Alberta alone (the provinces for which complete data is available). CIHI extrapolated these numbers to all of Canada and determined that there were approximately 170,000 allergy-related ED visits in 2013–2014.
Visits for anaphylaxis, a severe allergic reaction that may cause death, represented about 8% of all visits for allergic reaction.
The rate of children younger than 18 who visited EDs in Ontario and Alberta for anaphylaxis more than doubled over the time period studied. Youth age 13 to 17 experienced the highest increase (23 per 100,000 in 2006–2007, compared with 59 per 100,000 in 2013–2014), while children age 4 and younger consistently had the highest rate of visits for allergic reactions annually. Children primarily presented with food-related reactions or unspecified reactions (where the cause of the reaction is unknown or not documented).
Visits for allergic reactions (including anaphylaxis) from all causes were highest in the summer months; visits for food-related allergies also increased in December.
“Our data indicates that hospital visits for allergic reactions increase during times of the year when people may not be in their regular routines,” said Kathleen Morris, CIHI’s vice president of Research and Analysis. “Visits for insect stings and snake bites spike in the summer months, and food-related reactions are slightly higher during the winter holiday season when many Canadians attend holiday parties.”
In 2013–2014, the top 3 allergy diagnoses in EDs were as follows:
- Allergy unspecified: 30,057 visits
- Urticaria (hives): 20,365 visits
- Venomous animals toxic effect (insect stings, snake bites, etc.): 13,448 visits
CIHI’s data also shows the following for Ontario and Alberta:
- In Ontario in 2013–2014, the North West Local Health Integration Network (LHIN) (Thunder Bay and area) had the highest rate of ED visits for allergic reaction (including anaphylaxis) at 730 per 100,000; the Mississauga Halton LHIN had the lowest at 381 per 100,000.
- In 2013–2014, the highest rate of ED visits for allergic reaction (including anaphylaxis) in Alberta was 960 per 100,000 in the North Zone (Fort McMurray, Grande Prairie and surrounding areas). The lowest rates were in the Calgary Zone (460 per 100,000) and in the Edmonton Zone (458 per 100,000). It is not unusual to see higher rates of ED visits in northern/more remote regions.
- The Calgary Zone was the only Alberta health zone whose rate of ED visits for allergic reaction (including anaphylaxis) experienced a substantial increase over the 7 years studied. The rate increased by more than 60%, from 283 per 100,000 in 2006–2007 to 460 per 100,000 in 2013–2014.
According to the Canadian Society of Allergy and Clinical Immunology, anaphylaxis is a serious allergic reaction that is rapid in onset and may cause death. 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 that, in its most severe form, is called anaphylaxis.
- Table 1: Number of visits to the emergency department for anaphylaxis and allergy in Ontario and Alberta, by diagnostic type, 2006–2007 to 2013–2014
- Table 2: Percentage of visits to the ED for allergic reaction (including anaphylaxis), by category and month, 2013–2014
- Table 3: Number of visits to the emergency department for anaphylaxis and allergy in Ontario and Alberta, by region, 2006–2007 to 2013–2014
CIHI collects and analyzes information on health and health care in Canada and makes it publicly available. Canada’s federal, provincial and territorial governments created CIHI as a not-for-profit, independent organization dedicated to forging a common approach to Canadian health information. CIHI’s goal: to provide timely, accurate and comparable health information. CIHI’s data and reports inform health policies, support the effective delivery of health services and raise awareness about the factors that contribute to good health and health care.
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