Can allergies make your mouth itch?

How allergies cause it

An itchy mouth after a bite of raw fruit can be a pollen allergy showing up at the table. In pollen food allergy syndrome (PFAS), also called oral allergy syndrome, allergens found in both pollen and raw fruits, vegetables or some tree nuts cross-react.¹ Some tree pollen is similar to proteins in these foods, and the immune system can’t tell them apart.³

If you have hay fever (allergic rhinitis) caused by pollen, your mouth or throat may become itchy after eating an apple or celery.² This happens in up to 50 to 75% of adults allergic to birch tree pollen.² People with PFAS typically have an allergy to birch, ragweed or grass pollen.¹

PFAS can cause an itchy mouth, a scratchy throat, or swelling of the lips, mouth, tongue and throat.¹ Itchy ears and hives on the mouth are sometimes reported.¹ Symptoms usually appear immediately after eating the raw food.² They usually fade quickly once the food is swallowed or taken out of the mouth.¹ People with PFAS can usually eat the same foods cooked, because heating changes the proteins and the immune system no longer recognizes the food.¹

An itchy mouth can also come from a food allergy: FDA lists a tingling or itchy sensation in the mouth among the symptoms of food allergies.⁴ If you are allergic to a food you have eaten, symptoms may appear within a few minutes to a few hours.⁴

Foods linked to each pollen

Not everyone with a pollen allergy reacts to these foods, but ACAAI lists them as commonly associated with each pollen. Birch pollen goes with apple, almond, carrot, celery, cherry, hazelnut, kiwi, peach, pear and plum. Grass pollen goes with celery, melons, oranges, peaches and tomato. Ragweed pollen goes with banana, cucumber, melons, sunflower seeds and zucchini.¹

AAFA adds alder pollen and lists almond, apple, celery, cherry, hazelnut, peach, pear and parsley for it.³ In people with a birch pollen allergy, even peanuts, almonds and hazelnuts may make the mouth itch.²

Season matters too. In many patients, oral allergy syndrome gets worse during the season of the pollen involved, but it can happen at any time of year.²

Allergies or something else?

The itch can come from PFAS or from a food allergy, so it helps to know the difference. With PFAS, it is rare for symptoms to spread beyond the mouth or to become anaphylaxis, although this has been reported in a very small percentage of patients.¹ In one study, PFAS progressed to systemic symptoms, beyond the mouth, in nearly 9 percent of patients and to anaphylactic shock in 1.7 percent.¹

Age is one clue. PFAS typically does not appear in young children.¹ It is more common in older children, teens and young adults who have eaten the foods for years without problems.¹ ACAAI lists fruit and vegetable pollen (oral allergy syndrome) among the most common food allergens in adults, along with peanuts, tree nuts, fish and shellfish.⁵

FARE counts an itchy mouth as a mild symptom.⁶ A reaction with mild symptoms in more than one area of the body, though, is a severe reaction.⁶

There is no definitive test for oral allergy syndrome.² People who have it often have a positive skin or blood test for a specific pollen, along with a history of symptoms after eating the suspected foods.²

When to see a doctor

If you always get an itchy mouth after eating the same raw fruit or vegetable, see an allergist for a diagnosis.¹ Talk to your doctor if the symptoms cause significant throat discomfort, keep getting worse, come from cooked fruits and vegetables or from nuts, or if raw fruits or vegetables bring on hives, vomiting or trouble breathing.²

Rarely, oral allergy syndrome can cause severe throat swelling that makes it hard to swallow or breathe.² If a reaction goes beyond the mouth area after eating a fresh fruit or raw vegetable, that food could be considered a risk for anaphylaxis, a serious reaction that comes on quickly and may cause death.¹ An itchy mouth or throat that comes with wheezing, throat tightness, trouble swallowing or dizziness, especially after eating, calls for medical care right away: call 911.⁷