155: Oral Allergies + Cross Reactivity: How It Can Trigger Itchiness + Hives w/ Rakhi Roy, MS, RD, LDN

Have you ever hard of oral allergy syndrome? No? Well, you're not alone. My guest today will share some surprising facts about oral allergy syndrome, as well as cross-reactivity within allergies.

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My guest today, Rakhi Roy Chowdhury, holds a Master’s in Dietetics & Nutrition and a BA in Anthropology & Theatre.

She is an actress-turned Registered Dietitian with more allergies than the average person. Her theater and film career had to take a back seat due to constant eczema flareups that prevented her from going to auditions and booking work.

After realizing nutrition played a pivotal role in managing her eczema, Rakhi embraced a change in career to devote her time to helping others like herself.

She is now a board licensed Registered Dietitian-Nutritionist, and helps others manage their skin conditions, balance digestive issues, and follow their bliss.

Join us as we dive into oral allergy syndrome: What is it? What is allergy cross-reactivity? And how can this impact the skin?

Have you experienced allergen cross-reactivity? Let me know in the comments!

In this episode:

  • What is oral allergy syndrome?
  • Different classes of allergens and cross-reactivity
  • Is oral allergy syndrome connected to the skin?
  • Is it possible to build a tolerance to the allergen?


“Oral allergy syndrome is a little bit more of a milder allergy. It usually never results in a life-threatening reaction. It might be really uncomfortable. There are instances where people will just eat the food and their mouth gets really itchy.” [1:31]

“There is no set standardized test for oral allergy syndrome at the moment, unfortunately. So you do really need to go to an experienced allergist. Someone who's actually an immunologist, who actually does the research.” [12:42] 


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155: Oral Allergies + Cross-Reactivity: How It Can Trigger Itchiness + Hives w/ Rakhi Roy, MS, RD, LDN FULL TRANSCRIPT

Jennifer: Thanks Rakhi, so much, for coming back to the show. I really appreciate it.

Rakhi: Thank you for inviting me. I'm so excited.

Jennifer: And I'm excited to talk about this topic, because I have found it really surprising that a lot of clients are unfamiliar with this concept of something called oral allergy syndrome and cross-reactivity within allergy. I don't even know what you call them. They're like allergen groups, a family, what have you.

Rakhi: Yeah. Food families.

Jennifer: Food families and pollen families and all sorts of things. And so basically, what they typically will say is, well, when I have, I'm just going to say like zucchini or plums, which is stone fruit, my mouth gets kind of itchy. And as you were saying before we started recording, this kind of fuzzy feeling.

Rakhi: Yeah.

Jennifer: And so can you talk a little bit about what's going on when someone eats a food, and it could even be berries, it can be a lot of different things, and they start to get this reaction in their mouth. But to them, it doesn't seem like an actual allergic reaction. What exactly is that?

Rakhi: Correct. So food allergies are lifelong threatening, can be permanent. Your symptoms can be hives, vomiting, it can affect your breathing, that sort of thing. Now oral allergy syndrome is a little bit more of a milder allergy. It usually never results in a life threatening reaction. It might be really uncomfortable. There are instances where people will just eat the food and their mouth gets really itchy. Their throat doesn't necessarily close up, but they might start wheezing a little bit. And that's because the body is actually confusing the fruit or the vegetable for the pollen, in the pollen family. So for example, birch a lot of times, it's very commonly reactive with apples, carrots, celery, cherries, kiwi fruit, peaches, pears, and plums. So that's the birch.

Jennifer: Oh my goodness.

Rakhi: I know. I know, but I actually do, there is hope though, because birch tends to be more prominent, the pollen tends to be more prominent in the springtime. And so in the summer, the late summer, fall time, you might actually be okay with it. My own father, he has an issue with cherries, so he stays clear of them in the spring. But during the winter seasons, he can have the cherry.

Jennifer: Oh, interesting.

Rakhi: And the other thing though, is the protein gets denatured when you do heat it, or you put it in acid. So for example, myself, I can't have a raw apple, but if it's cooked in say, an apple pie, the heat denatures it, because you baked it and then my body doesn't recognize the protein and I don't have that reaction. A lot of times you can also peel the skin. So if you peel the skin, the proteins, a lot of times are in the skin, so you can do it that way. What other, Oh, so like I said, acid, so you know, those little snack packs at the grocery store where the apples are kind of peeled or you might be familiar with it, whoever goes to McDonald's, the little kids' meals-

Jennifer: Yeah, I think it's in the different convenience stores too. They have little peanut butter cup or sunflower cup or whatever.

Rakhi: Yeah. So in those instances, I always tell people, you might not have a true allergy, right? You always, of course, I say refer to your allergist, immunologist, do a test first before you try it out on your own. But almost always, when it comes to these types of fruits and vegetables, it's usually an oral allergy syndrome. So you might be safe to try the apple and the baked pie or the one that's in the snack packs, because it's usually preserved in a citric acid.

Jennifer: Right. And so basically, the issue here is that some people are finding that there's these random foods that are causing this weird oral issue. And they're like, well, it's funny when I dig, I'm like, but what about this? Oh yeah, that too, that too. And a client recently shared with me that he discovered a pretty severe ragweed allergy and ragweed is related to stevia. And stevia is a sweetener that's in a lot of supplements and protein powders and all sorts of things for people that want to avoid cane sugar and extra sugar, because they don't want to spike their blood sugar, but they want it sweeter. And so, we were also saying too, that calendula is another herb that's in that family as well. Calendula is an herb that oftentimes is used in different skin care formulations, because it can be a very healing herb. But for some people, they may react to it because again, they're allergic to ragweed. And so can you talk a little bit about what are some of these different classes? So you mentioned birch and what are some others that you're familiar with?

Rakhi: So there's birch, there's ragweed and there's grass. So the ragweed, you mentioned the calendula. I believe there is also a relation to dandelion as well in there somewhere. So yes, it's all these herbal teas that you're told are so great for you, especially for skin and liver support, you might have a reaction to. And I feel like a lot of people continue to take these products thinking that this is supposed to be helping them and it's, they would never guess it's this. But when you have no rhyme or reason, you don't know what to look for, it's a mystery. So when you find out the connections and the families like the grass, the ragweed and the birch, and knowing what seasons they're more active, you can actually find it at the American Academy of Allergy Asthma and Immunology.

Rakhi: If you go to their website, they have this beautiful list of all these foods and you can see what seasons that they're actually more active, so that means you don't have to avoid it lifelong. Another one that's really interesting is latex. If you have a latex allergy, you might have a reaction to banana, avocado, chestnuts, kiwi, figs, apples and cherries. Now those are more oral allergy syndrome, not as severe, but I was at a conference where an allergist did present on cross-reactivities for severe allergies, specifically peanuts. And I can talk about that if you're interested?

Jennifer: Yeah. I think people would love to hear that, because there's a lot of people that have nut allergies, a lot of moms with kids who listen that have nut allergies and peanuts are off the table. So what would that, what does that entail?

Rakhi: So, and I found this out, unfortunately through my own experience. So peanut allergies, I think it's like 1 in 10 people that have a peanut allergy. So in America, I think the numbers were if you go on the food and allergy research website, I think the number is somewhere around 6 million people have a peanut allergy. Now on there, you'll also find that people who have a peanut allergy, had a 5% chance of also having a severe reaction to soybeans, legumes, lentils, peas, and chickpeas. And it was really funny because in my own experience, this has happened so many times, I can now tell that there's chickpeas or peas in this. But I used to have a favorite ice cream and it was a dairy free ice cream, if anyone's familiar with the brand, So Delicious. So it's just coconut milk, really great and then all of a sudden, they changed their formula because now food companies are trying to put more protein into their products to just market the protein content.

Rakhi: And because they understand a lot of people are probably vegan who are buying their products, they end up not putting whey protein in there, they end up putting vegan sources. And a great vegan source right now of protein is pea protein. So that was an unfortunate event for me to find out. There's so many other other times where it's like, I was thinking I had a gluten-free pizza or gluten-free Miyaki at a restaurant and I didn't even think to ask them, what is the flour they use? And it was chickpea flour. So this does not affect everyone, but it is something to look out for, especially if, there's a higher rise in peanut allergies. I know that's being reported. This is something to be mindful of.

Jennifer: And I think this is a good question. So this isn't like a, we're not talking about anaphylaxis here in this particular conversation. We're more talking about this oral allergy issue and cross-reactivity. But from your personal experience, is there a crossover between exposing yourself, like say you have a ragweed allergy and you consume stevia not knowing that they're connected, is it possible that you could have issues on your skin as a result? Even though, like I said, most of the time for a lot of people, it's just what's going on in their mouth. They're like, “Oh, my mouth feels really funny.” Like you said, maybe they start to wheeze. What's your thoughts on that as far as the connection to the skin?

Rakhi: So from my research and also personal experience, it's usually just limited to hives, or just itchiness. It usually doesn't transpire into eczema. However, there is a research study that I was reading on the, I can't quote, which was the Clinical Allergy Journal and they did find that only 1% of people who have eczema, also have a peanut and a soybean allergy. That's the only one that they found a connection to eczema or rashes. But most of the studies I found with oral allergy syndrome, it's usually just hives.

Jennifer: Okay. And hives, could the hives be full body or in just particular spots or just around the mouth?

Rakhi: Yeah, it can be full body.

Jennifer: Oh, wow. So this could actually be an explanation for some people as to why they're developing hives randomly. And they're like, “I don't know what's going on. I wasn't exposed to birch. I wasn't outside.” And yet, they eat something that was cross-reactive in the birch pollen family, so to speak.

Rakhi: Yeah, absolutely. And then the other thing is, it's like a trend that I see, it's only eat raw food. Raw food is healthier than cooked. And I'm like, sometimes actually that might cause an issue for somebody and don't forget juices. There's a lot of juices, like I mentioned, celery is in birch family. So, the popularity of a lot of juices incorporating celery into their products, can be a problem. And, it's really funny when people say they don't feel good, I've heard this so many times, they don't feel good drinking a celery juice. Their stomach gets upset. I'm like, you might actually have an oral allergy syndrome. If you feel like you're vomiting, that's one of the symptoms of oral allergy syndrome. You might have a reaction. So my advice for people is to definitely make sure you're going to an allergist immunologist to check what your environmental allergies are, because it's not always that you're going to have a positive reaction to food, but the environmental allergies can be clues to cross-reactivities in food, in relation to oral allergy syndrome.

Jennifer: And just as a, and obviously you're not an immunologist or an allergist, but you've gone through this yourself. Any thoughts on, if someone does go to an allergist or an immunologist, what would be, is the patch test something that you find or through research seems to be the best way? Is blood IgE values better? Any thoughts on that?

Rakhi: So, it's actually a combination of all three, from what I found in the research. There is no set standardized test for oral allergy syndrome at the moment, unfortunately. So you do really need to go to an experienced allergist. Someone who's actually an immunologist, who actually does the research. And they need to kind of weigh the options of looking at all three. They will probably put you under an oral test, like a challenge test. That's kind of unfortunately the gold standard sometimes, just to see if there's a reaction. You'll be kept in the office for a couple hours and they'll monitor your symptoms. Now there are studies being done that are underway that they're trying to actually do oral immunotherapy, so that way you don't have to endlessly avoid these foods for life. The short term is obviously to cook it down, like I said, to denature the proteins. But, I'm thinking longterm, as more studies come out and more research is done, that hopefully there will be some relief for people that they don't need to avoid it.

Jennifer: Yeah. And I also want to clarify, because a lot of times people get the terms allergy intolerance and sensitivity very confused. We are talking about allergies here, okay. So this is not like you ate something today and four days later you had a headache.

Rakhi: Right.

Jennifer: Those delayed reactions tend to be more quote, unquote sensitivities. Whereas an intolerance has to do with you being missing or low on a particular enzyme like lactase, right? We all know the lactose out, the lactose intolerance, right? So this is very different. This is looking at a different part of your immune system. It's not the same as saying I'm gluten sensitive or I'm sensitive to dairy. This is very different. And I think it is important that people take these things seriously. I think any type of allergy, especially if you're constantly exposing yourself, and this is just my personal opinion, I tend to be very cautious. Even when it comes to oral allergy syndrome, I think a lot of people are kind of flippant about it. “Ah, it doesn't matter, not a big deal.” And I'm like, “You don't even carry Benadryl with you in your bag.”

Jennifer: I just kind of think sometimes people don't take these things as seriously as they should, because it could be one time where your body is just like, nope and then you've got an anaphylactic problem and it's something random that you wouldn't have expected. So I just think it's important to identify these types of issues and better understand that your body is reactive to things and knowing it's obvious now, that knowing those environmental allergies could be really important. And I also think it's a great point that you brought up, that in this particular case, if you do have oral allergy syndrome, cooking the foods is one easy way to get around this.

Jennifer: So it stinks. If blueberries or cherries are your favorite, well, you just kind of cook them a little bit and now you've got, you don't have as big of an issue.

Rakhi: Yeah. Put them in your pancake. That's what I do. It's delicious.

Jennifer: Exactly. You're like I can do it now.

Rakhi: Yeah.

Jennifer: I'm curious, with grasses, the grass family, just out of curiosity, if you know, is it any grasses or are there different groups based off of the different types of grasses, grass allergies, that there are?

Rakhi: The ones that are on the American Academy of Allergy and Asthma Immunology website, they specify Timothy and orchard grass.

Jennifer: Yeah.

Rakhi: So that's the one wherein all kinds of list off what they have. So the Timothy and orchard grass sometimes will be reactive, mostly in the summer is what they find. And it will be peach, cantaloupe, honeydew, watermelon, basically all the melons. And then there'll be kiwi, tomato and let's see celery again and actually white potato. White potato.

Jennifer: That's interesting. So somebody who might think that it's an issue with nightshades, right?

Rakhi: Yeah.

Jennifer: There's a bunch of nightshades in there. It might not actually be the nightshades, it could be something like this.

Rakhi: Absolutely.

Jennifer: It's unfortunate, it's very interesting, but I can tell, I just know, some people were probably like, Oh, this makes it so much more muddy. What exactly is going on?

Rakhi: Right. I have so many people who are like, “This makes so much sense now. It's not in my head.” I have so many people when I brought this up to them where I'm like, “You don't need to actually avoid all these foods. You've just got to cook it down.” But it's like, these are the relations and they look at me like, my life has just come together now, because no one's really talking… I really don't think a lot of doctors even understand oral allergy syndrome. You won't really hear it from a primary care physician. I actually never heard it from my allergist. It's really weird. Never.

Rakhi: In my years of growing up, I never heard of it. The first time I actually heard of it was when I went to this conference a few years ago, but I already put the puzzle pieces together on my own and then it was just kind of confirmed.

Jennifer: And so, since you have a lot of issues personally, I think it's helpful for people to know that aside from cooking these foods down, you and I both share the same concern. And especially with skin issues, people can go on pretty excessive elimination diets and they're like, I'm going to take this out. I mean, look at these lists. These are some really healthy foods.

Rakhi: Absolutely.

Jennifer: I'd be sad if someone just thought, well, I've got to avoid all of this. So what is one of the steps that you plan on taking for yourself that maybe somebody who's dealing with a lot of these different issues, might want to consider?

Rakhi: Oh yeah. So definitely, I don't want to ever have to avoid all these delicious fruits and vegetables the rest of my life. There's currently oral immunotherapy that's being researched. So that's something that I definitely plan on going to an immunologist to get this handled as well. They do say that having allergy shots might help lessen your quote, unquote immune system bucket. So I used to get allergy shots for years when I was younger. And so that might actually, by default, if you lower your reaction to birch per se, during spring season, it might actually help you, when you're eating that food too at the same time.

Jennifer: So basically, when you're saying, because I just want to make sure people understand what this means. So they're exposing you to small amounts of the allergen to help your system become less reactive?

Rakhi: Right. The hope is for you to build up a tolerance. And this is monitored under supervision of a qualified professional. And they will be exposing you to small doses of this in the office until they feel like you're at a tolerable threshold. A lot of times this does take at least a minimum of a year. I've seen that. It's not going to be happening overnight, but it's definitely an option.

Jennifer: Yeah. And I just want to say, first of all, thank you for even mentioning this to me, because when you had told it to me, it's so funny this came up, because I forget what we were talking about and then you had said, do you want to share this story real quick about the mixed drink that you had and how this whole conversation got started? It's so random. But it goes back to the chickpea issue you mentioned.

Rakhi: Yes. Yes. So I think Jen had posted something on her Instagram about Aquafaba.

Jennifer: Yes, yes. So that's the chickpea water, like when you drain the can of chickpeas or you cook them, you'll end up with this kind of thicker slightly, I don't know, it becomes slightly more gelatinous as it cools, but usually it's just a thicker water and it's called Aquafaba.

Rakhi: Yep. Yeah. So I never knew what Aquafaba was, but when I was finishing grad school, I was doing my masters down in Miami for my dietetics degree. They actually get really fancy with their drinks down there. I don't know if anyone's ever gone to Miami. It is fun. So their bars don't, I love a tequila sour and I used to order tequila sours that use just a sour mix, meaning it was that artificial lemon, lime, whatever, and maybe red dye, who knows what's in there? And this one time I ordered a tequila sour, the true way a tequila sour gets made is actually with Aquafaba, because they have to make the top of it foam. So, they put it in the shaker and the Aquafaba starts to expand. It's very much like, I would say almost like egg whites.

Jennifer: Yes and it's used in vegan cooking like egg whites.

Rakhi: Yes. So they did that. And on the top it was very filmy and pretty and I was like, Oh, this is cool. The moment I took two sips, my stomach hurt so bad, I knew I had to throw up and my body it's kind of like a memory. Allergies are very much like memories. And I was like, I know for a fact I probably had something that had chickpeas or something peanut related, because my body will react the same way every single time. And allergies of course, are very dangerous, because you can one day, knock on wood, I've never had to use an EpiPen for this situation, but you can have a very lethal reaction the more times you're exposed to this.

Rakhi: And so, every single time my body has had more and more of a violent reaction. So it's come to the point where now I do have to carry around a card with me or put on my phone, my allergies. If I'm ever going to a Mediterranean restaurant, there's one time I was in the airport of Dubai and they were making pizza. It wasn't even, I asked them, did you make this pizza out of something? But, it was just literally in the vicinity of where they were making it and chickpea is very relevant there. So that was, yeah.

Jennifer: Yes. So that's what started this whole conversation. I was like, we should talk about this, because it is an issue for more and more people. And a lot of people are unaware of what oral allergy syndrome is. And until you really showed me the extensiveness of these families based off of what type of allergies you have, I didn't even know, because I don't work with people that have severe, severe, severe allergies. So it wasn't something that was even really my wheelhouse, per se. And I'm like, we need to talk about this, because this may really help open some people's eyes who are struggling. Especially from a lot of these issues that are more allergic, hives, itchiness, et cetera, to hopefully find a better balance with their body, with their diet and make peace with food, ultimately and know that there are ways around this. But I think it's great that you're also educating people about it and your own experience, because if you do have serious allergies, you're right, you got to take it seriously.

Jennifer: And sometimes you need to carry a little card or something on your phone that you can show people that's in different languages when you travel to make sure that you're not accidentally exposing yourself to something that could ultimately one day, and we don't know when that day is, cause a major issue. But at least for now, this, I think, gives people a good semblance of what they need to consider. So if you have any of these allergies, right? You're like, Oh yeah, I'm really allergic to birch pollen or these grasses or ragweed, et cetera, this may be a good opportunity for you to dig deeper and say, let me check out this website to look at these lists and see if some bells start ringing in your head about, ooh, that's a problem. That's a problem. Oh yeah.

Rakhi: Yeah. And I also want to add, of course you can go to the website that I had mentioned for American Allergy and Asthma Immunology. They have the list. You can download the PDF. If you do have environmental allergies, I do recommend downloading an app. It's called Allergy Cast. I think it's made by Zyrtec. And what's really nice is you track five days of your symptoms and they'll tell you outside if it's high, moderate or mild for, I think today, I live in Florida, so it's high for grass, for example. And so I will track my symptoms and then it will usually tell me something, an allergy impact score. So on those days, I know maybe I should probably avoid what's probably being grown in season or at least cook down the foods.

Rakhi: And then of course, like I said, longterm, you do want to go to an immunologist and see if you can actually handle this more longterm, rather than short term avoidance. And then there's another app, I think it's called My Foods Symptom Diary. Because I think the most important thing for a lot of people, is not just writing down what you're eating, but you have to know what you're looking for. So now that you know what the clues are, you can kind of piece them together, because for the longest time there was no rhyme or reason for me. I'm like, I'm just randomly reacting to apricots and apples. What is that? It never made sense. And then all of a sudden, it kind of came together.

Jennifer: I know and I'm hoping that this conversation will put those pieces together for a lot of the people listening. So I just want to thank you so much for joining us again.

Rakhi: Of course. Thank you.

Jennifer: And everybody can go find Rakhi. As I said, she's a dietician and she has a lot of experience with eczema, especially because she is living that life. She's an amazing eczema warrior herself, so she has a lot of empathy for people that are struggling with that. Her website is littleblissnutrition.com. And she's also got a great Instagram. If you're over there, it's gut.skin.nutritionist. So Rakhi, thank you so much for joining us. I really appreciate it.

Rakhi: Thanks so much, Jen. I appreciate it too.

“Oral allergy syndrome is a little bit more of a milder allergy. It usually never results in a life threatening reaction. It might be really uncomfortable. There are instances where people will just eat the food and their mouth gets really itchy.”

Jennifer Fugo, MS, CNS

Jennifer Fugo, MS, CNS is an integrative Clinical Nutritionist and the founder of Skinterrupt. She works with women who are fed up with chronic gut and skin rash issues discover the root causes and create a plan to get them back to a fuller, richer life.

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