What you should know about food allergies

By Dr. Jiang

One of my favourite months of the year is December. It’s the best time of year to relax, get together with friends and family, and indulge in delicious treats. Whether you are hosting a dinner or going out to a party, you probably will know or meet someone with a food allergy, or maybe you have an allergy yourself.

Allergies can happen when the body’s immune system identifies something that we come in contact with as harmful, and releases chemicals like histamine in response to it. Examples of allergens can include pollen, grass, dust, pet dander, bee stings, medications (like penicillin), and food. People can be exposed to allergens by ingesting them, breathing it in (like pollen), or absorb them through skin. For people who are very sensitive, just a tiny amount of an allergen can trigger a severe reaction.

Any food can potentially cause an allergic reaction, but the most common food allergies include peanuts, tree nuts (like hazelnuts and almonds), sesame, egg, wheat, shellfish, fish, milk, and soy.  When the body’s immune system activates and releases histamine in response to food in the body, it can cause allergy symptoms like itchy mouth and hives on the skin. More serious symptoms can include swelling of the lips, throat, and face; vomiting, diarrhea, abdominal cramps, dizziness, lightheadedness, and difficulty breathing. If a person develops these symptoms, they are going into anaphylaxis, which can be deadly and require medical attention as soon as possible.

If a person develops symptoms that may be related to an allergy, they can be referred to an allergist by their family physician. An allergist is a physician trained in diagnosing and treating allergies, and they can diagnose allergies by doing skin prick tests, blood tests, or oral challenge tests. Once an allergy is diagnosed, there are ways to manage the condition. For someone with a food allergy, the best way to manage the allergy is to avoid the food trigger. They should carry an Epi-Pen, which is an injector filled with epinephrine. Epinephrine, or adrenaline, is a medication that’s used to stop an allergic reaction, especially if the person develops anaphylaxis.

If you or someone you know develops an allergic reaction from exposure to a food, it’s important to administer epinephrine via the Epi-Pen and call 911 for an ambulance straight away.  It’s recommended that people with food allergies carry two Epi-Pen with them at all times, as they may need a second injection. It’s important to teach family members, friends, co-workers, and caregivers how to use an Epi-Pen, and what to do if someone ingests an allergen and develops an allergic or anaphylactic reaction.

Questions around introducing new foods to babies and food allergies are ones that I get asked regularly by new parents. The recommendations for introducing common food allergens like peanuts have shifted in recent years. The recommendation now is to introduce potential common allergens early, as early as 4-6 months of life. There have been studies that show early exposure to potential allergy-causing foods can actually decrease the risk of developing allergies to these foods later in life. If you have any questions or concerns about introducing new foods to your baby, I recommend speaking to your family physician or your child’s pediatrician.

There are many more interesting facts about food allergy that I didn’t include in this article. Visit foodallergycanada.ca for more information about food allergies and food intolerance.


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