Oral Allergy Syndrome (OAS) or Food Pollen Allergy

by Jeanne on April 8, 2013

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
-vomiting
-diarrhea
-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.

-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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