Why Does Fresh Fruit Make my Mouth Itch?

Summer brings a bevy of fresh fruits—peaches, watermelon, kiwi, cherries, apricots and more.
But as tasty as those fruits may be at the height of the summer season, eating them can be miserable if you have oral allergy syndrome (OAS), also known as pollen-food allergy.

Why Does Fresh Fruit Make my Mouth Itch

(Pixabay / 9767269)

If OAS is your cross to bear, when you bite into a perfectly ripened peach, your mouth may start to itch. You will then have to decide if you can live with that reaction and eat your way through that bag of gorgeous peaches you just brought home from the farmers market—or if the reaction is so irritating that you have to miss out on summer’s bounty.

So what causes this reaction, and what can you do about it? Read on for answers to some frequently asked questions about oral allergy syndrome.

What causes oral allergy syndrome?
If you are allergic to pollens (from trees, grass, weeds, etc.), you probably react to them with hay fever-like symptoms during pollen season (usually spring or fall). These pollens contain proteins that your body has learned to recognize as being “bad.” (They’re not, of course, inherently bad, but your immune system gets confused and thinks of them as threats such as viruses or bacteria.) When you encounter these pollens in nature, your immune system launches a chemical response to “defend” itself, which includes releasing histamine into your body. The result is all of those allergy symptoms that make you miserable—sneezing, itchy eyes, a runny or stuffed up nose, and perhaps even coughing or wheezing.

So what does this have to do with fruits and veggies? Unfortunately, due to the complexities of pollination, some of the proteins in fruits, vegetables and nuts closely resemble the proteins found in pollens. As a result, when you bite into a fresh food item, your body may believe it is under attack and launch an immune response that you will feel in your mouth, throat and lips. You may experience swelling, tingling and itching.

Is oral allergy syndrome dangerous?
Not usually. The vast majority of oral allergy syndrome reactions are irritating—but not serious. The challenge is knowing whether you are experiencing OAS as a by-product of pollen allergies, or if you are legitimately allergic to the food item itself.

Most people are not allergic to fruits and veggies, but they may be allergic to tree nuts, which can trigger OAS. An OAS reaction to tree nuts will usually stop with the uncomfortable symptoms in the mouth, but a true tree nut allergy could progress to include life-threatening respiratory problems and low blood pressure.

How do I know if I have OAS or a true food allergy?
If you can tolerate the fresh food in question when it is peeled, processed, or cooked, you probably don’t have a true allergy to that food item. This is because the proteins that cause oral allergy syndrome are often found on the surface of the fruit or vegetable, and they are very easily broken down with heat.

To be sure of the scope of your allergy, you should consult an allergy doctor. They can discuss your symptoms and perform a food allergy test, if appropriate, to assess your allergies.

Which pollens cross-react with which foods?

Here’s a closer look at common pollens and the food proteins that they resemble.

Trees (usually birch and alder)Apple, apricot, cherry, kiwi, nectarine, pear, plum, peach, prune, persimmon, strawberryBeans, carrot, celery, green pepper, potato, parsnip, peasAlmond, hazelnut, walnut, peanut, soybean, sunflower seeds
GrassDate, Kiwi, cantaloupe, honeydew, orange, tomato, watermelonPeas, potatoPeanut
RagweedBanana, watermelon, cantaloupe, honeydewCucumbers, zucchini
Mugwort (a common weed)Apple, cantaloupe, honeydew, orange, peach, tomato, watermelonCarrot, celery, green pepper, onion, parsnipSunflower seeds

Birch trees (as shown in the first row) are the most common culprit behind oral allergy syndrome.

Why do my OAS symptoms feel worse at different times of the year?
You may notice that your symptoms get worse when the offending pollen is in season. For example, if you are allergic to birch tree pollen, you may have greater difficulty tolerating apples, apricots and cherries in spring when birch trees are pollinating.

What should I do if I have oral allergy syndrome symptoms?
The most important thing to do is rule out an actual food allergy—particularly where nuts are concerned. If you only react to fruits and vegetables, try eating cooked versions and seeing if you can tolerate them. If so, you probably have OAS. If the symptoms are very bothersome to you, you may have to give up those foods or try sticking with peeled or cooked versions of them.

Another option is to pursue allergy immunotherapy in the form of allergy shots (subcutaneous immunotherapy) or allergy drops (sublingual immunotherapy). Talk to your allergy doctor to decide which treatment is better for you. Both have been shown to be effective in reducing pollen allergies, which can, in turn, reduce oral allergy syndrome symptoms.

More insurance companies cover allergy shots, but shots require a lot of time because you have to go to the doctor’s office a couple of times per week for injections. Allergy drops are safer and have been approved for home administration, so you can take them on your own terms, which saves a lot of time.

Talk to your doctor to help you weigh the cost of allergy drops against that of allergy shots. While some insurance plans won’t cover allergy drops, by the time you account for co-pays and time lost traveling to and from the doctor’s office, many people find the price tags of the two forms of immunotherapy to be comparable. Most insurance plans cover allergy testing and office visits regardless of which type of immunotherapy your doctor prescribes—whether it be shots or drops.

With fresh produce being one of the healthiest things you can consume, it just seems wrong that the body should react negatively to it. Fortunately, there may be ways around it so that you can have your fruits and veggies and feel good, too.

About The Author

Stuart H. Agren, M.D.

Stuart H. Agren, M.D. completed his undergraduate studies at the University of Utah and went on to earn his Doctor of Medicine from Tulane University School of Medicine in 1974. He completed additional training at L.D.S. Hospital in Salt Lake City, Utah and then established his private medical practice starting in 1975. Dr. Agren completed a mini-residency in Industrial Medicine at the Robert Johnson School of Medicine at Rutgers University and also completed training to become a certified Medical Review Officer.

Dr. Agren was the Medical Director at TRW and McDonnell Douglas in Mesa, Arizona and at Stauffer Chemical and Kennecott Copper in Salt Lake City, Utah. He also served as an adjunct faculty member at Arizona State University.

In his private medical practice, Dr. Agren specialized in family practice and allergy. In his work as a private practice allergist, he was one of the first doctors in the country to prescribe sublingual immunotherapy to his patients as an alternative to subcutaneous immunotherapy (allergy shots). He has also been a trailblazer in the field of food allergy treatment and research, developing a program to treat multiple food allergies simultaneously using sublingual immunotherapy. Dr. Agren has been featured on local CBS, NBC, and ABC news affiliates and won the peer-nominated “Top Doc” award from Phoenix Magazine.

After 20 years in private practice, Dr. Agren became the Founder and President of AllergyEasy, which helps primary care physicians around the country offer allergy testing and sublingual immunotherapy treatment to their patients. Over 200 physicians in over 32 states use the AllergyEasy program to help their patients overcome environmental and food allergies and asthma.