Peanut Allergies

When you have peanut allergy, your immune system mistakes peanut
protein as harmful. Your body responds to it by having an allergic reaction.

Children commonly outgrow food allergies. However, allergies to peanuts, tree nuts, fish, and crustaceans and molluscs are usually lifelong.

Yes. Although anyone can develop a food allergy at any time, the tendency toward allergic reactions is largely inherited. Where there is a history of atopic disorders (such as asthma or eczema) or other allergies, children may have two to four times the likelihood of developing an allergy as compared to children from families without allergic parents.

Yes. Though most individuals develop food allergies in early childhood, food allergies can develop at any age.

Anaphylaxis is a rare but potentially fatal condition in which several different parts of the body experience severe allergic reactions simultaneously. This may include swelling of the mouth and throat, a drop in blood pressure, unconsciousness, hives and other symptoms. Anaphylactic reactions can be mild to life-threatening and can occur within minutes to four hours after exposure to the allergen, requiring immediate medical care. Emergency treatment often includes injection of epinephrine. Persons with food allergies often are prescribed epinephrine to carry with them at all times in the event of anaphylaxis.

Peanut is a part of the legume family and is not a tree nut; however, while peanuts and tree nuts are different, in some cases people with
a tree nut allergy may also react to peanuts. If you have a peanut or tree nut allergy, consult your allergist before eating tree nuts that are
not a regular part of your diet. (Source)

Peanuts are a complex plant food, with more than 30 different proteins. Research is underway to identify exactly which proteins trigger an allergic reaction, and why the reaction can vary in severity among those with peanut allergy. In Canada, the priority food allergens include crustaceans and molluscs, egg, fish, milk, mustard, peanut, sesame, soy, tree nuts, and wheat and triticale.

No, simply smelling the aroma of peanuts is not the same as breathing in protein particles which may cause an allergic reaction. The chemicals which are detected as the odour of peanuts are aromatic molecules called pyrazines and, alone, are incapable of causing allergic reactions.

Food allergy is a growing public health issue. Some hypothesize that the lack of early childhood exposure to infectious agents and parasites has increased susceptibility of allergic disease. The lack of early childhood exposure to peanut and infrequent consumption of peanut once introduced have also been linked to increased peanut allergy. It’s difficult to determine if the increased reports of peanut allergy are due to actual increases in incidence, or a result of increased awareness among consumers and health professionals.

Epinephrine is the first-line treatment for a severe allergic reaction (anaphylaxis). It helps to slow the progression of the reaction and is more effective if given early. Follow these 5 steps:

1. Give an epinephrine auto-injector (e.g., EpiPen^® or ALLERJECT^®) right away.
2. Call 9-1-1 or your local EMS immediately and tell them someone is having an anaphylactic reaction.
3. Use a second auto-injector as early as 5 minutes after giving the first dose if there is no improvement in symptoms.
4. Go to the nearest hospital right away (ideally by ambulance), even if symptoms are mild or have stopped. The reaction could get worse or come back.
5. Call emergency contact person (e.g., parent).

An allergist may give you personalized advice for the steps to take after an epinephrine auto-injector is given (step 1).

The only certain way to prevent a reaction is avoidance. With proper management, awareness and education, most reactions to food allergens can be avoided. You can also speak to your allergist about other possible treatments for peanut allergy.

Individuals with food allergy should diligently read all food labels and ask questions about foods prepared away from the home (such as at school or a restaurant). In the day care or school setting, parents of a child with food allergy should inform teachers and school staff, so they are prepared to recognize and treat severe allergic reactions immediately and seek first aid.

In consultation with their physicians, individuals with food allergy and at risk of anaphylaxis should always carry their epinephrine auto-injectors and should also consider wearing an identity bracelet or medallion to alert others that they have food allergy.

The amount of a food required to cause a reaction varies by person, and in some people, it can be triggered by a small amount.

The process of refining oil significantly reduces or, in some cases, removes the protein which would trigger an allergic reaction. Highly refined oil typically does not pose a problem for those with allergies. However, oils which are cold pressed to retain their flavour, or oils that have been used to cook peanuts do contain protein and therefore should be avoided. Before consuming products with highly refined oils, you should discuss with your allergist to determine if these products can be an option for you.

Peanut protein remains in the food during heating. You cannot completely remove it through heat.

Diagnosing a food allergy may not be difficult if a person always has the same reaction after eating a certain food. However, foods are generally eaten in combination. It is therefore important to consult a certified allergist to determine if the symptoms are caused by food and if so, which one.

Food allergies are diagnosed by taking a thorough medical and dietary history, keeping a food diary, eliminating suspect foods, conducting skin tests, and evaluating food challenges. It is important to consult a board-certified allergist if you suspect you have a food allergy. Allergists can accurately diagnose the allergy and prescribe medication for its treatment.

Most allergy sufferers experience mild reactions. Symptoms can include varying degrees of hives, swelling of the throat, difficulty breathing and vomiting. A small proportion of susceptible sufferers may experience severe and potentially fatal anaphylactic shock.

Yes. It is possible that peanuts could be found in unexpected foods, including, but by no means limited to, the following:

• Sauces such as chili sauce, hot sauce, pesto, gravy, mole sauce and salad dressing
• Sweets such as pudding, cookies, and hot chocolate
• Egg rolls
• Potato pancakes
• Pet food
• Specialty pizzas
• Asian and Mexican dishes
• Some vegetarian food products, especially those advertised as meat substitutes
• Foods that contain extruded, cold-pressed, or expelled peanut oil, which may contain peanut protein
• Glazes and marinades

To learn more about food allergies, check out Food Allergy Canada's online resources and learning tools, available on allergyaware.ca. This is a free, medically-reviewed resource designed for people with potentially life-threatening allergies and those who care for them. 

For more information about food allergies, you can also visit the websites below:

• Food Allergy Canada
• Canadian Allergy Asthma and Immunology Foundation
• Canadian Society of Allergy and Clinical Immunology
• Prevent Peanut Allergies
• Health Canada

Recommendations for the introduction of common allergens, like peanuts, to infants have changed as research has emerged on ways to help prevent the development of food allergy in babies.

A 2021 position statement co-published by the Canadian Paediatric Society (CPS) and the Canadian Society of Allergy and Clinical Immunology (CSACI) includes recommendations on the specific timing of early introduction of allergenic foods for high-risk infants. The current guidance is to actively offer non-choking forms of foods containing common allergens (e.g., peanut) around 6 months of age, but not before 4 months, as this can be effective in preventing food allergy.

Infants who are not considered high-risk should start to receive complementary foods when they are around 6 months of age.

Infants must be developmentally ready for solid foods.

It is recommended that the food is not placed on the baby’s skin. This is because food smeared on a baby’s skin may cause skin irritation that can be mistaken for allergy.

Keep in mind that whole peanuts are a choking hazard and should not be given to children under four years of age. Prepare peanut as follows:

1. To 2 tsp of smooth peanut butter, add 2-3 tsp of hot water
2. Stir until dissolved and well blended
3. Allow to cool

This mixture can be offered alone or added to an already tolerated infant food (e.g., cereal, pureed fruit). Another option is a peanut puff product (e.g., Bamba), which can be softened for younger infants.

Global research indicates that early introduction alone is not enough. Once an infant has eaten peanut protein, and if there is no allergic reaction, it’s very important to keep feeding peanut protein to the baby. It is recommended to feed peanut protein at least once a week to help prevent the development of a food allergy. In 2023, the CSACI further reinforced the critical role of regular ingestion in food allergy prevention.

Feeding allergenic foods for the first time in most babies is safe. It rarely causes a severe allergic reaction. If an allergy is suspected to peanut or another food being introduced, stop offering that food and speak to the doctor right away. Ask your doctor to refer you to an allergist as soon as possible to explore early oral immunotherapy, which may prevent your baby from developing lifelong food allergy. Continue introducing other allergenic foods without delay. If there are severe allergy symptoms, seek immediate medical attention/call 9-1-1. (Source)

In general, there is still insufficient evidence to recommend changing a mother’s diet to prevent food allergy (i.e., by avoiding or ingesting particular allergenic foods during pregnancy and while breastfeeding).

Specific to peanut allergy, some studies suggest that mothers who consume peanut while breastfeeding may decrease the risk of peanut sensitization, provided this is done in tandem with the early introduction of peanut protein in the infant’s diet. However, these studies remain insufficient to support a recommendation to actively consume peanut protein during breastfeeding. (Source)

• Food Allergy Canada
• The Canadian Paediatric Society
• Prevent Peanut Allergies