Oral Allergy Syndrome or Pollen Food Allergy - The Facts

by Kathi MacNaughton Health Professional

People often ask questions here about itching in the throat, mouth and nose. While it's true that this type of itching is frequently related to nasal allergies, it could be something more too, a condition known as Oral Allergy Syndrome (OAS for short) or pollen food allergy.

With this condition, people who have certain types of pollen allergy also react to certain fruits and vegetables. So, while the pollen triggers runny nose, nasal congestion and sneezing, the food triggers an itchy, tingling mouth or lips when eating it.

What's the Connection?

Experts have found that there are similar proteins between certain types of pollen and some fruits and vegetables. Ragweed pollen is the most common cross reactive type of pollen. People with ragweed pollen allergy may also react to the following:

  • Bananas

  • Chamomile

  • Cucumber

  • Echinacea

  • Melons, such as watermelon, cantaloupe, honeydew

  • Sunflower seeds

  • Zucchini

But birch tree pollens cause problems too, when the following foods are eaten:

  • Almonds

  • Apples

  • Carrots

  • Celery

  • Cherries

  • Hazelnuts

  • Kiwi

  • Peaches

  • Pears

  • Plums

  • Potatoes

  • Pumpkin seeds

And those of us allergic to grass pollen can develop OAS as well, if we eat these foods:

  • Kiwi

  • Melon

  • Peaches

  • Tomatoes

As you can see there is some overlap among the different types of pollen and fruits. If you happen to be allergic to tree, grass AND ragweed pollen (like me), then you'll need to watch for symptoms any time you eat any of those foods

Because the problem proteins tend to break down easily with processing and cooking, you are much more likely to react to fresh foods, rather than to cooked varieties. So if, for example, you have a grass allergy, you might react to fresh tomatoes, but not to pasta sauce or pizza. Other people can eat apples without their skins or certain varieties of apples without problems.

In addition, if you have OAS, you will probably find that the trigger foods only bother you during their related pollen season or that they are much more prevalent or severe then. For instance, if you have ragweed allergy, it's likely that you will only notice the OAS symptoms during the late summer and fall, when ragweed pollen is at its peak.

Symptoms of Oral Allergy Syndrome

Itching of the mouth, tongue, throat, and lips are some of the most common symptoms of this condition. But you may also have tingling, irritation, mild swelling, or hives in those areas. The good news is, the symptoms will usually go away if you stop eating the food.

If you notice these symptoms, be sure to consult with an allergist. Any allergy symptoms related to food should always be evaluated by an allergy specialist, because of the risk of anaphylaxis. These experts can diagnose you, tell you which foods you should avoid and prescribe treatments to relieve your symptoms.

What Risks Should You Be Aware of?

Most people with OAS have only mild, short-term symptoms. But in some people, these seemingly mild symptoms may be a hint of more severe reactions to come. There are studies that suggest that as many as 9 percent of people with OAS may have more severe symptoms of food allergy down the line. Up to 2% are at risk of life-threatening anaphylaxis.

In addition, OAS may be a warning of a more severe latex allergy.

In summary, although OAS itself is a fairly mild condition, it should not be ignored, because more severe symptoms may be lurking in the wings. So, make an appointment with an allergist today to discuss your treatment options!

Kathi  MacNaughton
Meet Our Writer
Kathi MacNaughton

Kathi is an experienced consumer health education writer, with a prior career in nursing that spanned more than 30 years — much of it in the field of home health care. Over the past 15 years, she's been an avid contributor for a number of consumer health websites, specializing in asthma, allergy, and COPD. She writes not only as a healthcare professional, but also as a lifelong sufferer of severe allergies and mild asthma, and as a caregiver for her mother with COPD.