Ask the allergist is a regular feature in our newsletters where Canadian allergists answer your questions!
Dr. Julia Upton is on staff at the Hospital for Sick Children in the Immunology and Allergy Department; and an Assistant Professor in the Department of Paediatrics at the University of Toronto. She is the past Section Chair of the Anaphylaxis and Food Allergy Section of the Canadian Society of Allergy and Clinical Immunology. Dr. Upton is also a member of our Healthcare Advisory Board.
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 a question about tree nuts, one of the priority food allergens.
Can you be allergic to just one type of tree nut, and if so, should you avoid all nuts?
Yes, you can be allergic to just one type of tree nut. Some tree nuts are very similar to each other and some are less similar. People allergic to cashew are usually allergic to pistachio, and people allergic to walnut are usually allergic to pecan. These nuts are so similar many allergists consider them in these pairs. The other nuts are less similar to each other.
Your allergist may be able to narrow down your tree nut allergy to a pair of nuts or a few nuts or maybe even just one tree nut. Your allergist will take into account your history of reactions to nuts, your other medical conditions and your testing to consider if you may not be allergic to some nuts.
An oral food challenge (OFC) may be offered to determine which nuts you are allergic to. An OFC is a supervised feeding, and you’d be given increasing amounts of the food in question to see if you are allergic to it. If you are, the OFC can also help determine your individual threshold, the lowest amount of a food allergen that can trigger a reaction. OFCs should only be done in a medical setting under the care of an allergist.
If there are tree nuts you tolerate, you can eat them in your diet. In particular, some people find it very helpful to find out if they are truly allergic to almonds. If not allergic, they can eat almond while avoiding other tree nuts. Your allergist can help with the education you need to do this safely. This includes knowing what tree nuts look like to minimize the chances of mistaking one nut for another and taking measures to avoid the risk of cross-contamination.
Do you have a question you’d like to ask an allergist in the months to come? If so, send it along to us at firstname.lastname@example.org. Please note: The allergists in this series answer questions on general topics, please talk to your doctor if you have questions about your own health or the health of your child.Tags: ask the allergist, dr upton, tree nuts