Do you have a cashew allergy? if you are allergic to cashew nuts, there are some other related foods that you might need to avoid too. And they aren’t all tree nuts. There are a few botanically similar foods that can cause food allergy reactions for some people who are allergic to cashews.
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What are cashew nuts?
Cashew nuts are a type of “tree nut”. This is a term used for nuts that grow on trees and shrubs, unlike peanuts which are a legume and grow in the ground. Other types of tree nuts include walnut, almond, hazelnut, pecan, pistachio, macadamia and Brazil nuts.
Tree nuts come from a number of different botanical families of trees. The cashew nut is from the Anacardiaceae family, and it’s botanical name is Anacardium occidentale. Cashew trees are tropical trees native to South America. They produce a red-orange fruit, called a cashew apple, and the kidney shaped “cashew nut” grows attached the bottom. The cashew nuts we eat are the seed inside of this. The outside skin or shell is inedible.
Symptoms of cashew allergy
Mild to moderate symptoms of a cashew nut allergy include:
- swelling of lips, face, eyes
- hives or welts
- tingling mouth
- abdominal pain and/or vomiting
More severe symptoms include:
- difficult/noisy breathing
- swelling of tongue
- swelling/tightness in throat
- difficulty talking and/or hoarse voice
- wheeze or persistent cough
- persistent dizziness or collapse
- pale and floppy (young children)
Like other food allergies, cashew allergies can cause serious reactions, including anaphylaxis. Anyone with a cashew allergy should have a written allergy action plan to follow in the event of an allergic reaction (and always carry emergency medication like an EpiPen if this has been prescribed by their doctor).
Foods that contain cashew
People who are allergic to cashews need to carefully avoid them. Tree nuts including cashews are often used in chocolate, cereals, muesli bars and baked goods. Cashews can be an ingredient in curries, dips and sweets like nougats and are also used to make cashew butter or nut based spreads. Vegan foods often use cashews to replace the creaminess of milk in sauces, vegan cheese and raw desserts.
Allergy to other types of tree nuts
It is possible to be allergic to only cashews. However, many people with a cashew allergy are allergic to more than one type of tree nut. The most commonly related tree nut allergy is an allergy to pistachio nuts. This is because cashew nuts and pistachio nuts are related to each other botanically. They therefore have similar proteins, and food proteins are what causes an allergic reaction. Our family deals with allergies to both cashew and pistachio nuts, as well as a number of other tree nuts.
If you have a cashew allergy, an allergy specialist can test for allergies to other tree nuts and give you advice about which types you need to avoid. Without testing, it is very hard to know which other nuts you might react to.
Surprising foods to be careful of (that aren’t nuts)
Some people with a cashew allergy can also be allergic to other foods that aren’t nuts. These foods are known to be “cross-reactive”. Again, this is because of the similar proteins found in these foods.
Sumac
Although it isn’t a nut, sumac can cause allergies in some people with cashew allergy. Sumac is a spice made from the dried and ground berries of the sumac flower. This red coloured spice is common in Middle Eastern cooking. It has a tangy, acidic flavour and is often used as part of a Za’atar spice blend. Sumac can also be used as a red dye.
The Sumac plant is botanically part of the Anacardiaceae family of trees, the same family as cashew trees. That’s why sumac can cause reactions for some people with cashew allergy.
Pink peppercorns
The attractive pink peppercorn is actually the pink/red berry of the Peruvian peppertree. They are often used in pepper mixes and other spice mixes. The berries look like pepper and have a peppery taste, but they are not actually relate to normal black pepper at all.
The peppertree which produces pink peppercorns is also part of the Anacardiaceae family of trees. It’s another member of the cashew family. Some people with cashew allergy react to pink peppercorns too.
Citrus Seeds
Unlike sumac and pink pepper corns, citrus trees aren’t part of the same botanical family as cashews. Instead they are part of the Rutaceae family, which is also botanically related to cashew trees.
Recently studies have found that some people with cashew allergy are also sensitised to citrus seeds. The protein which causes reactions isn’t found in the fruit itself, but in the seeds (especially orange seeds, but also lemon seeds and seeds from other citrus varieties).
Not everyone with a cashew allergy will be allergic to sumac, pink peppercorn or citrus seeds. Our allergist has just advised us to be cautious with these foods and watch for any sign of allergic reaction. We avoid sumac, but so far pink peppercorns and citrus seeds haven’t caused us any issues. Which is great news, as we eat and cook with oranges and lemons all the time.
Of course, if you have a cashew allergy and have any concerns about eating other foods that might be cross-reactive, you should ask your allergy specialist.
References and more information
For more information about cashew nut allergy and possible cross reactivity with other foods, see the following resources we’ve referred to in this post:
- Australian Society of Clinical Immunology and Allergy, Peanut, Tree Nut and Seed Allergy
- Australian Society of Clinical Immunology and Allergy, Dietary Avoidance – Treenut
- Shanna Bastiaan-Net et al, IgE Cross-Reactivity of Cashew Nut Allergens, Int Arch Allergy Immunol 2019;178(1):19-32;
- World Allergy Organisation Journal, Cosensitization to fruit seeds in children with positive cashew nut and/or pistachio skin prick tests (2020) 13:100137
If you are allergic to cashew nuts or other tree nuts, make sure to read our post on substitutes for nuts in your favourite recipes. Or check out our recipe page for lots of recipes that are completely nut free.
*Disclaimer: Allergy Spot does not provide medical advice. You should always consult a suitably qualified medical practitioner in respect of your own medical conditions, symptoms or concerns. See our Website Terms for more details.
