Can you identify the first signs of food allergy?

With over one in 13 Canadians affected by a food allergy, being able to spot it early can mean the difference between a spouse or child going into anaphylactic shock at the new restaurant in town or ordering their meal without the trigger.


Owen Wiseman

30 July 2016

What are food allergies?

Our immune system is constantly battling against pathogens such as bacteria and viruses to protect us from getting infected and then becoming ill. When a pathogen enters the body, whether through a cut, mouth, nose, etc., the body quickly mobilizes its forces to defend against the invader.

On the surface of these invading cells are something known as antigens which act like the war flags of that particular invader. When the body recognizes an incoming war flag, it tries to take action and expel the pathogen. You may notice that you start to get a runny nose as the body tries to trap the pathogen in mucus and then get rid of it. You will start to experience cough symptoms trying to ensure it doesn’t enter the airways, and certain enzymes in and on the skin, start to be produced more rapidly to make sure bugs fail to find a foothold. 

Some pathogens will successfully run the gauntlet however and get past all of our barriers. In the case of allergies, they are an overreaction of the immune system to typically harmless or innocuous compounds in the environment.

How does this happen?

Sometimes, when a food such as peanuts enters the body for the first time and is absorbed through the gastrointestinal tract, the body may misidentify it as something come to kill us. The immune system is designed to evolve and when it kills an invader, it steals its war flag antigen to study it so the body can respond faster and more effectively next time via the production of antibodies. So after eating that first peanut, if it’s mistakenly identified as the misunderstood villain in the tale, then the body will react strongly with each subsequent exposure to peanuts.

What kinds of signs and symptoms accompany an allergic reaction?

As mentioned earlier, you’re likely to notice a runny nose and coughing in addition to the following :

  • Hives – there’s a compound released by the body known as histamines that are triggered in response to these allergens. They increase blood flow to an area often leading to swelling and leaky capillaries as the vessel enlarges. This leaky vessel allows fluid to seep out and form a hive that lasts a couple hours at most.
  • Itchiness – the way histamines work is by binding to certain receptors which causes a cascade of reactions that lead to their ultimate conclusion and action. When they bind to histamine receptors, they promote a state of hypersensitivity and they put your ‘itch’ nerves on high alert. Antihistamines help prevent the signal to the brain telling you to itch the location.

While this can be minor, an allergic reaction may send the individual into a state of anaphylactic shock, a serious and life-threatening state. The airways of the individual begin to swell, becoming smaller and making it more difficult to breath. As the individual fails to bring in adequate oxygen, signs of dizziness, weakness, or even fainting may occur. The eyes, lips, and tongue may all begin to swell as well leading to difficulties with vision, speaking, or swallowing respectively. In severe cases like these, lifesaving medication such as epinephrine must be administered to the individual before their condition deteriorates.

How can I spot a food allergy early?

As an adult, it’s quite possible to suddenly develop an allergy to something you’ve enjoyed your entire life. You may notice that the shrimp ring that once brought you so much pleasure suddenly leaves you feeling bloated. Over time, other signs and symptoms discussed earlier may start to appear. You’ll notice your throat feels tingly, your lips may become a little swollen, and you may need to run to the bathroom for fear of throwing up. 

Becoming familiar with the signs and symptoms is a great way to catch the allergy early, but with infants it becomes more difficult because of the obvious lack of speech to say, “My throat is getting itchy”. You may notice that your little one starts to push a certain food away that they once ate with gusto. While they may be fussy, just take note of the event and monitor them every time you serve that food.  

I’m suspecting a food allergy, but I’m not quite sure as to what… 

Luckily, your friendly neighbourhood allergist can help solve the mystery. These physicians specialize in the immune response and how the human body responds to allergens, so they are quite skilled at determining what triggers your specific hypersensitivity reaction. 

The ‘Big 8’ of American food allergies are eight foods that represent over 90% of all food allergies in the United States. They are milk, eggs, fish, shellfish, tree nuts, peanuts, wheat, and soybeans. Health Canada lists Priority Allergens that reflect this list with the addition of sulphites, sesame, and mustard that require distributors to meet specific labelling requirements to protect that health of all Canadians.

Symptomatic relief can be found with products such as Allergy Relief which come as a nasal spray, a tincture, or tablets to meet your preference. This homeopathic preparation is sugar, lactose, and gluten-free and leaves out the drowsy side effects of many over-the-counter antihistamines. A clinical trial was carried out using the tablets with 88.5% of patients reporting an improvement in their symptoms while those using the nasal spray reported a significant improvement in their sneezing and nasal congestion.