Oral Allergy Syndrome (OAS) or Food Pollen Allergy

Note: I am not a medical doctor.  The following is provided for informational purposes only and should not be used as a replacement for speaking with your doctor.

Fruit bowl clip artI first learned of Oral Allergy Syndrome (OAS), also know as Food Pollen Allergy, also known as Food-Induce Pollen-Associated Oral Allergy Syndrome, when Girlfriend was in kindergarten.  One of the parents was struggling with many odd food allergies that her doctors couldn’t explain.  She reacted to greens (like kale) when she ate them raw.   I was interested in what could be going on, so I did some research.  At the time (2005) there wasn’t much info out there.  I finally found a personal blog where the person had the same reactions to things that my friend did and he called it Oral Allergy Syndrome.  Thus began my travels into the wacky world of how pollen allergies can affect reactions to food.  And, as it turns out, I am a major OAS sufferer.

What happens in OAS is a cross reactivity between plant pollens and fruit, vegetable, and nut proteins.  It’s actually a pollen allergy—not a food allergy.  So food allergy testing doesn’t help identify it.  Which is really confusing.   The only testing to be done is for pollen allergies to the pollens that cross react with the foods you’re reacting to.   Every time I have a new reaction my allergist looks at my pollen allergy chart and says, “yep, you’re allergic to birch trees (or whatever the appropriate pollen is).”

One thing about me: I’m allergic to everything.  When I got my official pollen allergy testing at my allergist’s office, she had the whole office come in to see my arm (where they did the skin pricks).  Apparently, I reacted the worst of any patient they had ever seen.  I react to everything.  And I have asthma—which also makes OAS more likely.  So, none of this is a surprise to my docs.

The primary culprits in OAS are tree pollens and grass and ragweed pollen.  So, if you react to those, then you may react to the raw foods that have similar pollen protein signatures (say that five times very quickly).    Sometimes the pollen protein signatures are things from the same botanical family, and sometimes they’re not.  And, further, you may react to one, some, or all–or none–of the raw fruits, veggies, and nuts that have the offending protein.  And, you may react to them during some times of the year and not other times of the year.   As you can imagine (or have experienced) this is confusing and annoying.

The reactions one can have to foods via OAS are varied.  Some of the reactions that OAS can cause:

-itchy mouth
-itchy throat
-swollen tongue–can be deadly
-swollen throat–can be deadly
-seized vocal cords (which make you sound like Daffy Duck—ask me how I know, thank you raw celery)
-stomach ache
-anaphylaxis–can be deadly (I get this from raw bananas)

Part of the fun of OAS (not) is that the reactions can happen some times but not all of the time.  I have found that some of my reactions occur all year, while others of my reactions happen most often during tree pollen season—late winter into spring.  What this means is that I can eat a salad with raw lettuce during the summer and fall but I can’t eat raw lettuce in the winter and spring.  The reason for this is that my body is already overwhelmed with allergies, and adding more pollen proteins to things just makes things worse.  This, as you can imagine, is confusing (and annoying) to friends and family members who can’t keep straight what you can eat and not eat and when you can eat and not eat them.

The other funky thing about OAS is that you can react to some of the things in a pollen category, but not to others.  Also, you can be allergic to a certain tree pollen and not react to any of the foods that bear the pollen protein.  Further, apparently OAS gets worse as you get older.  So, I have been slowly losing things from my diet.  For example, up until Girlfriend was in 1st grade, I could eat raw carrots with abandon.  Then, out of the blue, I started getting stomach-ache when I ate raw carrots.  I also started getting stomach-ache from apples.  As it turns out, these two are linked by the protein signature.  Each year, I seem to react to a new raw thing.  I joke that I may be stuck eating air pretty soon.  And as I looked back on my life, I realized that I had stopped eating all melons because they make my mouth itch.  Melons are high on the list of OAS foods.

The thing that is very odd about OAS (on top of all of the other odd things) is the fact that once you cook any of the things you can’t eat raw, it’s usually fine to eat.   For example, I get a really bad stomach ache and horrendous diarrhea when I eat raw zucchini (so no raw “zucchini noodle” salads for me).   But, if it is cooked well, I can eat it by the plateful.  This is why I microwave grated zucchini before I put it into zucchini bread.  I found out the hard way that the baking process doesn’t cook the zucchini enough for me.

And, because OAS isn’t logical (at least to me), there are some things you can’t eat even when cooked.  Broccoli falls into this category for me.  It makes me extremely ill even when I cook the heck out of it.  Be on the alert for these types of things.

If you suspect that you have OAS, you might want to talk to you doctor about it.  And be aware if you experience difficulty breathing or a swollen throat when you eat something.  This is a sign of potential anaphylaxis and it can be fatal.  If this is you, you need to make an appointment with your doctor to prescribe an epi-pen.  Apparently, about 2% of OAS sufferers have anaphylaxis to some of the foods they react to.  This is me and bananas.  I found this out the hard way one when I was sitting in on a class one day and ate a banana as a snack and all of a sudden, felt my throat closing up.  Oddly, I had eaten a banana the day before and had been just fine.  This is how bizarre OAS can be.

OAS Survival Tips

-If it makes you feel bad, don’t eat it.  It’s not worth it.

-Experiment with peeling your fruits and veggies.  Apparently, the pollen proteins are found in high quantities in the peel.  So peel your apples, peaches, nectarines, cucumbers, etc. and see how you feel when you eat the raw peeled fruit.

-On the other hand, be aware that you may react to contact with the thing.  Many people on the OAS group that I’m a part of react to peeling potatoes.  So, they have to wear gloves to peel the potatoes, but then they can eat them once peeled and cooked.

-Keep a diary of what you react to and when.  My experience shows me that I react to some things year round and other things during high pollen season.

-Cook things well.  Just lightly steaming something isn’t going to help for most of these things.   I have found that lightly roasting nuts doesn’t help.  They need to be well roasted.  Also, dried fruit and vegetables tend to be OK to eat.  As are canned fruits and vegetables.

-Identify those things you CAN eat raw.  It turns out that I can eat cauliflower raw.  But not broccoli or cabbage.  Who knows why, but I will take it.  Cauliflower and dip is an excellent party choice.  I always make a beeline to the veggie tray at parties and load up on cauliflower.

-Be aware that you may react to more and more things as time goes by.  Just be on the alert for this.  I have learned the hard way not to eat any raw things at parties or restaurants if I’m not absolutely sure that I won’t react to it.

-This may sound odd, but if I am at a friend/family member’s house and they are serving raw veggies, I ask if I can steam/roast/or boil some of them.  I just nip into the kitchen and do this.   Clearly, this is best done in a kitchen that you know well, but it is possible.  And I am sure to clean up after myself.  Also, at this stage, some of my friends just know to steam things for me before I arrive—which is very nice!

-Ask you doctor about allergy shots to the corresponding pollens.  There isn’t a lot of data out there on the effectiveness of allergy shots, but it’s worth a talk with your doctor if this appeals to you.

More information on OAS can be found here and here.

One last note: many OAS information sites/sheets don’t list nuts. But nuts are part of the issue, too.

image from wordplay.hubpages.com/hub/vintage-victorian-flowers-and-fruit

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  1. Mary says

    I once as a child told my ENT about my issue and he told me to see a dentist… and basically nobody believed me, they just thought I was a picky child who didn’t want to eat fruits or veggies.

    Bananas are my worst as well, but recently I found a banana pancake recipe (just 1 banana and 2 eggs) and I’m in love with it because I can finally taste a banana again without being absolutely miserable.

    • says

      Mary: I’m so sorry you had to go through that as a child. It’s interesting how little doctors know about OAS, even now. I get messages all the time from people whose doctors have no idea what’s going on. It’s strange to me. Also, I’m so glad you found a banana recipe you like–yay!

  2. busymommy00 says

    Could coughing and throat wheezing also be brought about by OAS? These are the main syptoms I get after eating what I believe is trigger food…mostly occuring during May/June/July time-frame.

    • says

      Busymommy: I’m not sure. It could be. I’m not a medical doctor. If it feels like your throat is closing up and you are having a hard time breathing, that could be a sign of anaphylaxis. I would talk to your doc immediately about this.

  3. Charlotte Herrington says

    Hi i just have to say a huge thank you for your blog. I thought i was going mad, i have been to and fro from the doctors getting tests for food allergies which come up negetive and now it all makes sense! I cant tell you what a relief it is to be able to find somewhere to listen to people who hae the same allergies as me. Mine have only just started in the past few years, and im terrorfied its going to get worse, my reactions are pretty severe already. As it stands, im alergic to hazlenuts, almonds, apples, cherries, plums, peaches, pears, carrots, rasberries and blackberries. Eating any of these things makes my mouth and throat swell in seconds and makes it hard to breathe, i also suffer from tummy aches. I will be going to do my doctor asap for help tomorrow now i know what it is – thank you xxx so much xxxx

    • says

      Charlotte: I’m so glad to be of help! And yes, it is kind of shocking how many doctors don’t know about this. I run into so many people with OAS who all say the same thing: their doc doesn’t know about OAS. And I think the number of people who have this is growing. Hang in there!

  4. Jan says

    Hi Jeanne: I too have OAS. It’s great to find your website and hear other people’s experiences with this confusing syndrome! For me, it has progressed over the last few years to allergic reactions to all raw or dried fruits and veggies, some spices (nutmeg, cumin, coriander, chili, paprika, anise), nuts, coconut (meat/oil), several cooked fruits and veggies (cherries, peppers, broccoli, cauliflower, bananas, strawberries, celery) and anything with capsaicin in it (peppers of any kind, paprika, chiles, chili powder, etc.). Just the smell of capsaicin sets off an allergic reaction. I also have allergic reactions to the juices in soda pop! It’s been quite a journey to get a diagnosis… I went through a few specialists before finally seeing the allergist who diagnosed OAS. My GP had never heard of Oral Allergy Syndrome – told me I couldn’t be allergic to so many things. He insisted it was psychogenic – so frustrating!). I had so many allergic reactions my body would go into random tremors. Thankfully, once the allergies were under control, the tremors stopped. It was a frightening, humbling experience. I have new respect and empathy for all those with food allergies and diseases that are difficult to diagnose. I am grateful every day that I can live a life where I can drive and enjoy my family. I have many food restrictions, but I am healthy and happy (and I can still eat some kinds of chocolate!). My reactions involve the airways, swelling, hives, and gastrointestinal. I carry an Epi-pen, ventolin inhaler and Benadryl with me whenever I leave the house. I am beginning immunotherapy this month. I’ve heard mixed reviews. My allergist says it may at least stop the progression – so I’m hopeful. Sorry for the long post – it’s been a bit therapeutic for me to share my story! Take care :)

    • says

      Jan: Thank you for sharing your story! It is so helpful to know that other people are going through the same things. I also have to carry an Epi-Pen, ventolin, and Benadryl with me wherever I go. And i is so hard to have a new reaction appear out of the blue. Yuck. I am so sorry that your doc was ill informed. Nowadays, it seems to be the thing to blame the patient if the doctor doesn’t know what’s happening–which really makes me mad. Hang in there–and let me know how the immunotherapy goes!

  5. Shira says

    I have had OAS for years, and its getting worse. Has anyone ever tried medications for it? My doctor wants me to take a med called xyzol- anyone ever heard of it?

    • says

      Shira: I haven’t taken it, but I’ve read that there are some intense side effects. Depending on the extend of your OAS, I’m thinking that it might be better to just avoid the foods that trigger your OAS.

  6. Laurie says

    I have been GF and DF and knew certain foods bothered me (apples potatoes almonds peaches melon walnuts)but broke out in a complete body rash after using a juicer with frozen bananas. After trying allergy shot unsucessfully, requiring EPI injections, I am at a standstill. I know I am allergic to many things cherries, hazelnuts, sometimes pineapples.
    I didn’f feel so alone reading these posts. Thanks

    • says

      Laurie: Oh, I’m so glad my blog is helpful. It’s interesting, I was at the farmer’s market yesterday and one of the farmers mentioned that he was encountering more and more people who can’t eat raw fruits and veggies. It’s becoming more common. Not that I love that other people are having problem, but it’s nice to know that you have peeps who are going through the same thing.

  7. Christie Cho says

    My 4Yr Old Daughter Has Multiple Food Allergies, Fructose Malabsorption, HOwever Symptoms Sound Similar. She Has Been Having On And Off Symptoms With Other Foods But Can’t Figure Out Which Is Causing A Reactiin. Do You Know If Sugars Also Causes A Reaction?

    • says

      Christie: The way OAS works is via the pollen that someone is allergic to in the air and the protein in the plants they eat that contain a protein that is similar to the pollen signature. So, I’m not clear where sugar comes into play. It sounds like she has sugar issues to begin with, right? I don’t really know, but my guess is that her sugar issues are a different problem–but I would ask her allergist to know for sure.

    • says

      Emily: Well, usually. There might be some things you cannot eat raw or cooked. For example, I am now having a reaction to cooked bananas in addition to raw bananas. But most other things that I can’t eat raw I can eat if they are well cooked. So, approach each thing with caution–cook them well before you try to eat them.

  8. emily d says

    Sorry didnt use my brain spell check this is what i meant to say I just found out I have oas and found out that I am allergic to soy, peanuts, chicken,pork, and cocunut I feel like I cant eat anything barely could you help find some recipes for me I need some good food

    • says

      Emily: Oh geez. I’m so sorry. Welcome to the club. Here’s what I do: I focus on what I can eat. It sounds like you can eat lots of stuff (although it probably doesn’t feel that way right now). Meat (except for pork), fish, rice, corn, other grains, beans, cooked fruits, veggies and nuts. And remember: it gets better. At first it seems horrible, but you get used to it and then you realize that you can actually eat a lot of things. Hang in there!

  9. Erin says

    Thanks for the info! I was diagnosed around 2005 as well and word seems to be spreading. I’m down to only being able to eat raw lettuce, grapes, and berries. I am allergic to everything else. I have found that I am allergic to apples, carrots, and cantaloupe in every form including cooked. I almost died (seriously) the last time I tried to eat applesauce and I passed out in a restaurant because of a stray sliver of carrot in my salad. Glad to know that there are other people out there with similar problems although, I would not wish this on anyone.

  10. says

    Hi Jeanne, great tips for dealing with OAS! I’ve got pretty severe OAS, and am actually finishing a book right now about it! I’ve just put a call out for feedback from the OAS community and would love to hear from you :)

    You can check out the book outline here: http://poorandglutenfree.blogspot.ca/2013/06/the-makings-of-oral-allergy-syndrome.html

    I’d also love for you to link-up your blog to my new OAS & GF bloggers page :)

    Thanks so much for sharing your experience, we need to raise awareness about OAS, there’s so little info available :)

    • says

      Danielle: Wow, a book on OAS? Awesome! Definitely a needed resource! Let me know what you can do to help you. I just signed up on your site for a blog link. Happy writing!

  11. Angela says

    I have had ugly allergies all my life (well, up until 6 years ago). I was on 4 shots a week and at least 6 oral meds a day. Everything under the sun affected me with the exception of shell fish. I know it sounds far fetched, but I tried an alternative treatment called N.A.E.T. (www.naet.com). I has made a huge difference. I feel human again. It uses acupressure to help your body not recognize things as allergens. It has been permanent for me. I am no longer on any shots and very rarely have to take meds. I thought it was too good to be true; but, I gave it a try. I figured it couldn’t be any worse than all the torture I was going through already. All I can say is that it has been a life safer! And a money saver. I can eat gluten now without getting the severe reactions as I once did (I still limit it) and I can function normally (well, my husband might not agree there but I at least feel human).

    I just want to throw it out there because it helped me and it doesn’t require any drugs and the results are at least 90% permanent. I never got that kind of response from any other kind of treatment. My results have been 100% permanent. I just go in for spot treatments now when something new comes into the air or I get sick for some unknown reason.

    Beyond that, I want to thank you for your blog and sharing what you know. It really is nice when you find that you are not the only “freak of nature” as my husband calls me. I feel that I am in good company and I really enjoy your style of writing. I am looking forward to reading more! :)

    • says

      Angela: I’m so glad that you’re treatment is working so well! I have heard of NAET and have heard of the fabulous results some folks get. And we are in the “freaks of nature” club–LOL!

  12. Cattaca says

    I highly recommend looking into the GAPS diet. Chances are your gut is leaky which is leading to an increase in food sensitivities over time. Cutting out foods alone is not the answer. I know I’ve been doing that for the last 10 years with no appreciable improvement in symptoms. GAPS is making the difference for me.

    • says

      Cattaca: You are absolutely right–a leaky gut is quite problematic. For me, it requires constant monitoring. I use megadoses of probiotics and I also use bentonite clay to absorb the toxins and to heal heal the gut. I find that my natural diet tends towards the GAPS protocol, with variations. Thanks for the suggestion!

      • Cattaca says

        Don’t forget the gelatine! I haven’t had time to do the from scratch none broths lately but I do have a large can of Great Lakes Gelatine which I add to just about everything. In a bout of mistaken overconfidence I had too much wheat a few weeks ago and a major leaky gut setback. The gelatine is making the difference.

          • Cattaca says

            Gelatine supplies the amino acids essential to the quick healing of the intestinal lining which is normally replaced every 3 days.

          • Cattaca says

            If the gut is not sealed all manner of improper and foreign substances can get into the blood stream and trigger an immune response. I tend to primarily show symptoms in my skin and yes having a tablespoon or two of gelatine every day along with raw milk, pastured eggs and lacto fermented vegetables are the cornerstones of my diet along with a good multivitamin. Like cheeseslave I think I’m making up for a lifetime of nutrient weak foods as modern agriculture has greatly depleted our soils.

  13. mommio says

    Thank you for writing about this. I am a highly allergic person and am just beginning to figure out that this is the reason why (since childhood) there are so many fruits I just don’t like.
    Do you ever get geographic tongue? I have gone through episodes of this as well and know that it is related to certain foods for me.
    Stupid allergies.

    • says

      Mommio: I just looked up geographic tongue–and it turns out I do have it. Wow. I had no idea. Thank you for the info. And I agree: stupid allergies.

  14. Michelle says

    This is such interesting, helpful information, and may explain why I have problems sometimes, but don’t others. I am so glad to have a name for it, and will be looking into it more. I really appreciate that you share this kind of information in addition to your terrific recipe!

  15. Chloe says

    I have OAS, but didn’t realise it could have gastro symptoms, thanks! I guess the name suggests its limited to oral symptoms. I’m taking part in a study at the moment on birch pollen immunotherapy and OAS, so hopefully there’ll be a bit more evidence out there!
    I also find my hands react to raw potato, especially when the skin is dry/chapped. I now have to wear gloves to peel them!

  16. Alexia says

    Great summary of OAS, our son has many of the same issues as you, it’s a real pain particularly in terms of nutrition, since cooking loses many vitamins..and he loves raw carrots and apples but definitively can’t eat them at the moment (he’s 4 and has many allergies other than OAS).

    Here in Europe, we do sublingual immunotherapy (SLIT) (instead of shots or in combination). Apparently the OAS may get worse at the beginning but then recedes. I don’t know if SLIT if FDA approved in the US tough.

    Thanks for sharing as always.

  17. odile says

    I have that with Kiwi fruit. I thought I was deadly allergic to it (anaphylactic) . It turns out it is a crossover allergy to a weed.

  18. Emily says

    I totally understand. I have OAS too. It started with just a mild response to bananas and carrots. Now it is those plus strawberries, apples, bean sprouts, potatoes, cantaloupe, honeydew, etc. etc. Like you said, it varies by the season. I have allergies to lots of pollens also. The worst for me is that I cannot even really peel potatoes anymore without an oral reaction, coughing, and starting to lose my voice. I don’t eat them at all. Hang in there!!

    • says

      Emily: Gah. I’m so sorry. It’s turning out that a lot of people react to potatoes and the process of peeling them. I need to be on the lookout for that. I realize that I kind of avoid potatoes most of the time–I wonder if this is why. You hang in there, too!


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