If you have ever noticed an itchy or tingly sensation in your mouth after biting into a raw apple, carrot, banana or any of the fruits and veggies listed here, read on.
People who are allergic to pollen are accustomed to runny eyes and sniffles this time of year. But some seasonal allergy sufferers have it worse: They can develop allergic reactions to common fruits and vegetables.
The allergic reactions — which are usually mild — can come on suddenly. And people can react to foods they had been eating with no problem for most of their lives.
The condition is called oral allergy syndrome. "I do think that this is one of the most underreported and underrecognized conditions, " says Dr. Carah Santos, an allergist at National Jewish Health in Denver.
People who have OAS are allergic to plant pollens. Many fruits and vegetables contain proteins that are similar to these pollens. So the immune system can mistake the fruit and vegetable proteins for the plant pollens that caused the allergy.
"We call it cross-reactivity," explains Santos. "Your immune system sees something as looking very similar to something it already reacts to."
Bananas were the trigger for Jessica Slattery, who lives in the suburbs of Denver. She began to notice a reaction every time she ate one.
"The first thing I'd feel is a little itch on my tongue," Slattery says. "I'd feel it down my throat ... it's just a little tingle."
Sometimes, her lips would swell, too.
When Slattery described the reaction to her friends, they were skeptical. "They were, like, 'How could you possibly be allergic to a banana?' " Slattery recalls.
Fruits are not on the list of top allergenic foods; most people have only heard of the top culprits such as eggs, fish and nuts.
But Slattery knew it wasn't in her head. Over time, she started reacting to other foods, including kiwi, pineapple and avocado.
She noticed she was most reactive to these foods during the spring and fall, when her pollen allergies kicked in.
The standard tests to detect food allergies often come back negative for people with OAS. This happened to Slattery. "I had testing ... for everything I thought I was allergic to, and everything came back negative."
This was frustrating, she says, because several doctors could not explain what she had. Ultimately, an allergist diagnosed her with oral allergy syndrome simply by taking a detailed history of her symptoms. She says it was a relief to get the diagnosis.
"It was like, 'OK, this is not in my head! It's a real thing,' " Slattery says.
People with oral allergy syndrome are typically advised to avoid the raw foods they react to. But there is a workaround: Peeling or cooking the fruits and vegetables before eating them can be helpful.
For instance, if apples cause a reaction, applesauce may be OK. Or if bananas are a problem, try banana bread instead. "Oftentimes [people with OAS] can eat these foods because the cooking process can degrade the proteins that look like the pollen," says Santos.
The prevalence of oral allergy syndrome is unknown, but researchers who evaluated pollen-related food allergies in 2015 concluded: "Although epidemiologic data are scarce, there is no doubt that the increase in pollen allergies is going to be followed by an increase in the so-called pollen-related food allergies."
Here are other tips on managing oral allergy syndrome from National Jewish Health:
- Avoid raw foods that cross-react with your pollen allergens.
- Take oral antihistamine medications to relieve mild symptoms.
- Bake or cook foods to degrade the protein and eliminate the cross-reaction.
- Eat canned fruits or vegetables during your pollen season.
- Peel the food, as the protein is often concentrated in the skin.
The experts at National Jewish Health advise that people call an allergist when OAS symptoms get worse or occur when eating nuts.
DAVID GREENE, HOST:
Many people complain this time of year about pollen allergies. They get those itchy, watery eyes, runny noses. You know what I'm talking about. But some people with seasonal allergies have it worse. They develop allergic reactions to common fruits and vegetables - everything from apples and bananas to carrots and cucumbers. NPR's Allison Aubrey examines this allergy syndrome that often goes undiagnosed.
ALLISON AUBREY, BYLINE: Several years back, Jessica Slattery began to notice a strange reaction every time she ate a banana.
JESSICA SLATTERY: So the first thing I would feel is a little itch on my tongue, and my lips would start to swell. And then I'd feel it all the way down my throat. And it's just like a little tingle.
AUBREY: And the reaction got worse in late spring, right around the time her seasonal allergies to tree pollen kicked in. Now, at first, she didn't go to the doctor because the symptoms were mild and because nobody she knew had ever heard of a fruit allergy.
SLATTERY: I did have some friends who were like, how could you possibly be allergic to a banana?
AUBREY: It's true that fruits are not the top allergenic foods. The usual culprits are eggs, fish, nuts. But over time, Slattery noticed that her reaction to bananas - that itchy, tingly sensation - spread to other fruits too, like kiwis, apples and avocados. Now, ultimately, she was diagnosed with a condition called oral allergy syndrome. Here's physician Carah Santos. She's an allergist at National Jewish Health in Denver.
CARAH SANTOS: I do think that this is one of the most underreported and under-recognized conditions.
AUBREY: She says Jessica Slattery's story is familiar. People with seasonal allergies or hay fever can suddenly develop allergic reactions to many common fruits and vegetables that they've eaten for most of their lives with no problem. Santos says what happens with this condition is that the immune system gets tripped up. It mistakes the proteins found in fruits and vegetables for the plant pollens that triggered the allergy in the first place.
SANTOS: We call it cross-reactivity. And that just means your immune system sees something as looking very similar to something it already reacts to.
AUBREY: Santos says it's not clear why the immune system suddenly starts reacting to foods that it has tolerated for years. That can happen in adolescence or adulthood. And the tricky part about diagnosing it is that the standard tests to detect food allergies often come back negative. That was Jessica Slattery's experience.
SLATTERY: I had testing through skin pricks for everything that I felt that I was allergic to. And everything came back negative.
AUBREY: Slattery says she went to several doctors who told her she was not allergic to these foods.
SLATTERY: When they're telling you that they've done this test and it's negative, you're like, OK, well, then it must be me.
AUBREY: That's why when she finally got the diagnosis, she felt reassured. Doctors made the diagnosis simply based on her symptoms.
SLATTERY: It was like, OK, so this isn't in my head. It's really a thing. And, you know, for me, it was a lot of relief.
AUBREY: People with oral allergy syndrome are typically told to avoid the raw foods they react to. But what they can do is peel or cook the fruits or vegetables before eating them. For instance, if apples cause the reaction, applesauce may be OK. Or if bananas are the problem, try banana bread. Here's allergist Carah Santos.
SANTOS: Oftentimes, they're able to eat these foods simply because the cooking process can degrade the proteins that look like the pollens.
AUBREY: This is the approach Jessica Slattery's taken. She's had to give up a lot of raw fruits, but she's found plenty of workarounds to maintain a healthy diet. Allison Aubrey, NPR News. Transcript provided by NPR, Copyright NPR.