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Ep. 42: What are cross-reactive allergens?

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This episode is sponsored by Allergy Insider.


Do certain foods make your mouth itchy? We may have the reason why!


In this episode, Dr. G and Kortney are joined by Dr. Wright, a board-certified allergist and Medical Director at Thermo Fisher Scientific, as they demystify cross-reactivity in food allergens. Cross-reactivity is a term that causes a lot of confusion around food allergies because it can be used in a few different ways, not to mention being misused.


Cross-reactivity in allergens will make more sense as the two allergists outline oral allergy syndrome (OAS), also known as pollen food allergy syndrome. We also chat about whether you could be allergic to a food that is cross-reactive to one of your allergens. Plus, what tests are available to determine whether it is a true allergen or something like OAS, and more! Kortney chimes in with her real-life experiences and many questions to unpack what cross-reactivity means in the context of food allergies.


What we cover in this episode:

  • What is cross-reactivity?

  • Cross-reactivity with pollen versus cross-reactivity between IgE mediated allergens.

  • What is oral allergy syndrome (OAS), and why do allergists prefer pollen food allergy syndrome?

  • The difference between OAS and true food allergies causing anaphylaxis.

  • How do you know it is an allergy due to pollen cross-reactivity (OAS)?

  • What are the symptoms of OAS?

  • How is oral allergy syndrome diagnosed?

  • Can you have anaphylaxis to foods that OAS causes?

  • Are there some fruits and vegetable varieties that are better for people to eat who have OAS?

  • When do people start to develop OAS?

  • Who would typically develop OAS?

  • The cross-reactive pollens and their cross-reactive foods.

  • The types of tests available for testing cross-reactive allergens: skin prick, blood test and component testing.

  • How to determine if a food is an allergen due to pollen cross-reactivity or IgE mediated.

  • Why would you consider getting component testing?

  • How component testing can help determine if you can tolerate baked eggs and baked milk.

  • How to determine if you are a candidate for an oral challenge.

Fun facts in this episode:

Component tests can help with egg and milk allergies!


Did you know that...

75% of people sensitized to egg can tolerate baked egg

70% of people sensitized to milk can tolerate baked milk


Listen to the end of the episode to learn how you may be able to test whether you can tolerate baked milk or egg.

Additional Resources:


Allergy Insider


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