Fruit and Vegetable Allergies Symptoms, Diagnosis, and Treatment

Oral Allergy Syndrome

Various chopped fruit and vegetables

Verywell / Zorica Lakonic​

The most common type of food allergy in adults is triggered by fruits and vegetables, not peanuts, tree nuts, or even shellfish. Although peanut and nut allergies tend to get the most attention, you're actually more likely to be allergic to nectarines and apples than you are to nuts.

Allergic reactions to fruits and vegetables stem from what's called oral allergy syndrome (OAS), a condition that causes a reaction to foods that are structurally similar to allergenic pollens. This is sometimes referred to as pollen-food syndrome (PFAS) or as a "class 2 food allergy." PFAS is more common in teens and adults.

Symptoms

If you have OAS, you shouldn't expect a runny nose. Instead, your symptoms will involve your digestive tract and skin.

These symptoms may include:

  • Itching or tingling of the mouth, tongue, or lips
  • Angioedema (swelling of the mouth, tongue, and/or throat)
  • Vomiting, stomach cramps, or diarrhea are less common
  • Anaphylaxis ( a severe allergic reaction) is very rare

Diagnosis

Diagnosis of OAS relies on a history of symptoms and allergy testing. Sometimes the diagnosis can be a challenge for you and your healthcare provider.

Your healthcare provider will ask you about your history of immediate reactions after eating certain fruits or vegetables, and also will ask about your history of seasonal allergies, hay fever, or a runny nose.

To identify the specific pollens and foods that are causing your symptoms, your healthcare provider may order skin-prick testing or RAST blood testing.

Because reactions vary depending on the freshness of the food and may vary based on whether the food was in direct contact with the skin of your mouth and tongue, testing results may not be accurate. For example, a capsule of prepared apple may not cause a reaction even if you have a reaction to eating a raw apple.

Cause

If you tend to have a runny nose during pollen season, you are more likely to develop OAS. Virtually all adults with OAS have a history of allergic rhinitis (a runny nose) due to pollen allergies.

OAS is caused by cross-reactivity between an inhaled pollen allergen and the proteins found in certain fruits and vegetables. While the pollen plant and the foods are not biologically related, the structures of their proteins are so similar that the body reacts to both.

Often, certain fruits or vegetables will cause a reaction when they are consumed raw, but not when they are cooked. For example, your mouth may itch after eating a raw apple, but you will be able to eat applesauce. This is because some of the proteins that cause pollen-related reactions break down when they are heated.

Specific Cross Reactions

The most common type of OAS in Northern Europe is birch pollen allergy. The American Academy of Allergy Asthma and Immunology notes that 50 to 75% of people with a birch pollen allergy also have some sort of OAS. Because birch pollen allergy is so common, it is the most widely studied of all OAS associations.

The following sensitivity associations for birch pollen, grass pollen, ragweed, and mugwort have been noted:

  • People sensitized to birch pollen may have OAS symptoms when they eat kiwi, apple, pear, plum, apricot, cherry, tomato, celery, carrot, fennel, potato, green pepper, cumin, pear, hazelnut, walnut, almond, peanut, lentil, beans
  • Grass pollen allergies are associated with sensitivities to melon, watermelon, orange, tomato, kiwi, potato, swiss chard, and peanuts.
  • Ragweed allergies are associated with sensitivities to watermelon, banana, zucchini, cucumber, and squash.
  • Mugwort allergies are associated with sensitivities to peach, lychee, mango, grape, celery, carrot, parsley, fennel, garlic, cabbage, broccoli, coriander, cumin, sunflower seeds, and peanuts.

More associations may be noted. The American Academy of Allergy, Asthma, and Immunology also has a table of associations.

Treatment and Management

As with most food allergies, the main method of managing OAS is avoiding trigger foods. Some people may only need to avoid their triggers in their raw form.

You may find that your symptoms are worse when pollen counts are high. During pollen season, you may need to avoid foods that you can tolerate at other times of the year. Your healthcare provider may recommend that you take antihistamines or other allergy medication to help control your allergic rhinitis symptoms.

There have been some studies showing that people who receive immunotherapy for birch pollen allergy are later able to tolerate raw apples. These studies were small, however, and there have not been studies done on other specific pollen-food interactions in immunotherapy.

A Word From Verywell

Oral allergy syndrome is a serious condition, and you'll need to manage your symptoms and watch your reactions carefully. You might need to cut back on some of the foods you enjoy, especially at certain times of the year.

Most adults with this condition do not need to carry an epinephrine auto-injector (commonly referred to by the brand name Epi-Pen). However, some people do have reactions that have the potential to be severe and are prescribed an auto-injector. Talk to your healthcare provider about the type and severity of your reactions to your trigger foods.

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4 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Seattle's Children's Hospital. Food allergy.

  2. American Academy of Allergy Asthma & Immunology. Oral allergy syndrome (OAS) or pollen fruit syndrome.

  3. Mastrorilli C, Cardinale F, Giannetti A, Caffarelli C. Pollen-food allergy syndrome: A not so rare disease in childhoodMedicina (Kaunas). 2019;55(10):641. doi:10.3390/medicina55100641

  4. Kashyap RR, Kashyap RS. Oral allergy syndrome: An update for stomatologistsJ Allergy (Cairo). 2015;2015:543928. doi:10.1155/2015/543928

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