Ask the allergist is a regular feature in our newsletters where Dr. Julia Upton answers your questions! Dr. Julia Upton is a Canadian allergist who is on staff at Toronto’s SickKids Hospital in the Immunology and Allergy Department. She is an Assistant Professor in the Department of Paediatrics at the University of Toronto and is the Section Chair of Food Allergy and Anaphylaxis with the CSACI.
Please note: Dr. Upton is answering as an individual allergist and her answers do not constitute an official position of her affiliated organizations. Her responses are for informational purposes only and do not constitute specific medical advice, recommendations, diagnosis, or treatment. Please talk to your doctor about any concerns or questions you may have regarding your own health or the health of your child.
This month she answers your questions about red meat and pea protein allergies.
Red meat allergy
Red meat allergy from a tick bite is on the rise in Canada. What are the signs and symptoms?
Red meat allergy comes from a tick bite which makes the person allergic to red meat. It is thought that the saliva from the tick creates the allergy in the bitten person. It is unusual for many reasons. One reason is that the allergy is to the carbohydrate in the meat (the alpha gal carbohydrate) rather than the protein.
Another feature which makes this allergy unusual is the delay (3 to 8 hours) from eating meat to the development of symptoms.
The ticks most associated with red meat allergy are the Lone Star ticks. These ticks have been found in small numbers in Canada. It is expected they will increase over time. Another way of exposure to these ticks is through travel.
The symptoms are the same as other food allergy, including a risk of anaphylaxis.
If you have food allergy already how do you know if you are reacting to the meat and not something that you are already allergic to through cross-contamination, etc?
This distinction would require a good history of what was eaten when there was an allergic reaction, as well as what is eaten without any problems. The timing of the food ingestion in relation to the allergic reaction would be very helpful. Red meat allergy is very rare currently in Canada.
How is it diagnosed?
The diagnosis is based on the history of food eaten, the timing of the symptoms, consideration of other causes, and sending a lab test for IgE to alpha-gal carbohydrate. This test is commercially available but may not be covered by provincial health plans.
Are there treatments?
The treatment currently is avoidance of red meat and carrying an epinephrine auto-injector. Successful oral immunotherapy to red meat has been reported although is not routine.
Will you be allergic forever, or does it resolve itself?
A person may not be allergic forever. The allergy may be more likely to resolve than other allergies. Your allergist would follow you overtime to assess if you have outgrown it.
Pea protein allergy
What is pea protein allergy?
This is a timely question with the desire for many people to eat plant proteins.
People can be allergic to any food. Pea protein allergy is where a person is allergic to peas, which is a legume. Peanut is also a legume.
What’s the cross-reactivity risk for those with peanut allergy?
On allergy skin testing and blood testing there is cross-reactivity with other legumes such as lentils and peanuts. However, this cross-reactivity does not mean that a reaction will happen when peas are eaten.
How do you know if you should avoid products with pea protein?
If you have eaten pea protein previously with no allergic reaction then you are very unlikely to have a reaction. You may be able to review foods you eat routinely and see that you have already eaten pea protein. There may also be differences in allergic reactions to regular pea rather than concentrated pea protein.
Pea is not a priority allergen so the labelling on certain types of products is not straight forward like it is for the priority allergens. If pea protein is an ingredient in a product it must be labelled, similar to other ingredients. However, if pea protein is a component of an ingredient, it may not be required to be labelled. For example, if pepperoni has pea protein as an ingredient, then the pepperoni product sold on its own would have pea protein listed in the ingredient list. However, if that pepperoni is used on a frozen pizza, then the pepperoni would be included by name in the list of ingredients, but it’s not required to provide all the sub-ingredients of the pepperoni unless one or more of these is a priority allergen. In this situation, pea protein would not be required to be listed in the ingredient list of the frozen pizza.
According to Health Canada, consumers with a known allergy to pea protein should read labels carefully and avoid any product that contains pea or pea derivatives as an ingredient. They should also be cautious about products which contain prepared meats as ingredients and should inquire with the manufacturer to ensure there is no pea protein present before consuming these products.
Who is at most risk of having a reaction? Is it just people with peanut allergy?
Anyone can be allergic to any food. However, people with other legume allergies are at higher risk.
If a person gets slight tingling by eating peas, should they stay away from pea proteins?
Mouth tingling can be a sign of a food allergy. Sometimes a reaction in the mouth is part of pollen food syndrome (pollen food syndrome is an allergy to a food due to a cross reaction from pollen). This symptom would need to be discussed with a physician.
How do you test for pea protein? Is there a substance available that allergists can use for testing?
The evaluation for pea allergy would include reviewing the foods suspected to cause a reaction as well as reviewing labels of foods that do not cause an allergic reaction. Skin prick testing can be performed with a commercially available allergy extract, or by using actual peas. Blood tests are also available for pea allergy.
None of these tests tell us for sure if someone will react when they eat the food. If someone has had symptoms of allergic reactions to eating peas and has positive tests then we would usually say they are allergic. The tests alone are not enough to label someone as allergic. Some people may need an oral food challenge to know for sure if they are allergic or not.
Thank you, Dr. Upton, for your insightful and helpful answers!
Do you have a question you’d like to ask Dr. Upton in the months to come? If so, please send it along to us at firstname.lastname@example.org.Tags: alpha-gal, dr upton, pea protein, peanut allergy, red-meat allergy