Fruit Allergies: Strawberries, Kiwi, Bananas and More

Oral Allergy Syndrome: When Pollen Is the Real Culprit

Many fruit reactions aren't true food allergies at all. They're a form of cross-reactivity called oral allergy syndrome (OAS), also known as pollen food allergy syndrome. Proteins in certain raw fruits look a lot like proteins in tree, grass or weed pollen, so a person with hay fever may get an itchy mouth, lips or throat when they eat those fruits.

The American Academy of Allergy, Asthma & Immunology explains that people with birch pollen allergy often react to fruits like apple, peach, pear, kiwi and cherry. Because the proteins involved are fragile, cooking or canning the fruit often removes the reaction. Symptoms usually fade within minutes, but in a small number of people they can spread beyond the mouth, which is why OAS is still worth discussing with a provider.

Strawberry Allergy

Strawberries are one of the most common fruits parents ask about, partly because they're a frequent cause of red, blotchy skin around a toddler's mouth. Often that's a contact reaction from the fruit's acids rather than a true allergy. True strawberry allergy does exist, though, and it's usually linked to a protein called Fra a 1, which is similar to the main birch pollen allergen. That's why many strawberry reactions behave like oral allergy syndrome.

Studies have found that Fra a 1 levels vary between strawberry varieties and with how ripe the fruit is, so some people notice they react to certain berries and not others. If you or your child has been tested and cleared by an allergist, fresh strawberries are back on the menu. Plenty of families like growing their own, and everbearing varieties such as Albion strawberry plants keep producing berries from spring into fall in many climates, so you can pick them at full ripeness.

Kiwi Allergy

Kiwi deserves extra caution. Along with pollen-related proteins, kiwi contains an enzyme called actinidin that can cause true systemic allergic reactions, including hives, vomiting and breathing trouble. Kiwi allergy shows up in both children and adults, and reactions can be more severe than with most other fruits. Anyone who has reacted to kiwi beyond a mild mouth itch should be evaluated.

Banana Allergy and Latex-Fruit Syndrome

Banana reactions are often tied to ragweed pollen or to latex. People with a natural rubber latex allergy can cross-react with banana, avocado, kiwi and chestnut, a pattern called latex-fruit syndrome. If you've ever reacted to latex gloves or balloons and also notice symptoms after bananas, mention both to your provider.

Other Fruits That Commonly Cause Reactions

• Peach and other stone fruits: can involve a sturdier protein (lipid transfer protein) that isn't destroyed by cooking, so reactions may be stronger.
• Apple and pear: classic birch-pollen OAS fruits, usually mild and limited to the mouth.
• Melon: often linked to ragweed and grass pollen.
• Citrus: less common, but can cause both mouth symptoms and skin irritation.

How Fruit Allergies Are Tested

An allergist will usually start with your history: which fruits, raw or cooked, how fast the symptoms started and where they showed up. From there, skin prick testing (sometimes using fresh fruit), IgE blood testing and component testing can help separate pollen cross-reactivity from a more serious allergy. Not sure whether your symptoms point to an allergy or an intolerance? Our guide to food allergy vs. food sensitivity breaks down the difference.

You can also see how strawberry and other foods appear on a typical lab report in our sample food allergy test results.