Oral Allergy Syndrome Food List, Chart, Diet and Treatment
- Oral allergy syndrome is an itchy or swollen mouth after eating certain raw fruits, vegetables or nuts, caused by food proteins that look like pollen to your immune system.
- Up to 50% to 75% of adults with birch pollen allergy get it.
- It's different from allergies to foods like shellfish, peanuts or wheat, which aren't tied to pollen and are more likely to cause severe reactions.
- Cooking, microwaving, canning or peeling often lets people eat the fruits and vegetables that bother them raw. If nuts make your mouth itch, see an allergist instead.
- Throat swelling, trouble breathing, hives beyond the mouth or vomiting after raw produce means a more serious reaction. Get care right away.
- Allergy shots may ease oral allergy syndrome in some people, but a 2024 review found too little evidence to count on it, so the main reason to treat is the pollen allergy itself.
Oral allergy syndrome (OAS) is an itchy, tingly or slightly swollen mouth right after eating certain raw fruits, vegetables or nuts. It mostly happens to people with pollen allergies, because some proteins in those foods look like pollen proteins to the immune system. OAS allergy is also called pollen food allergy syndrome. It's common: the American Academy of Allergy, Asthma & Immunology (AAAAI) says it affects up to 50% to 75% of adults with birch pollen allergy. The foods involved depend on which pollen you're allergic to, and cooked versions are usually fine. It's also just one kind of food reaction, separate from allergies to foods like shellfish or peanuts, as explained below.
When to get care right away
Most OAS reactions are mild and stay in the mouth. Rarely, they don't. Cleveland Clinic says to call 911 or go to the ER for swelling of the face, tongue or throat, trouble breathing or swallowing, or weakness and dizziness after eating. If you've been prescribed an epinephrine auto injector, use it right away, even before calling 911, as MedlinePlus advises.
What is oral allergy syndrome (OAS allergy)?
Oral allergy syndrome is an allergic reaction to food that starts with pollen. Your immune system learns to react to a pollen, such as birch or grass. Later it meets a similar protein in a raw apple or a peach and reacts to that too. Allergists call this cross reactivity.
The reaction usually stays in the mouth. According to Cleveland Clinic, stomach acid tends to break down the proteins before they cause trouble anywhere else. Heat breaks them down as well, which is why a baked apple often causes no symptoms when a raw one does.
The American College of Allergy, Asthma and Immunology (ACAAI) notes that it usually shows up in older children, teens and young adults who ate the same foods for years with no problem.
Oral allergy syndrome vs. food allergy
When a restaurant asks about food allergies, it usually means a different kind of allergy than OAS. Knowing which one you have changes how careful you need to be.
- Classic food allergies. The ACAAI's food allergy guide says nine foods cause about 90% of food allergy reactions: eggs, milk, peanuts, tree nuts, fish, shellfish, wheat, soy and sesame. The FDA names the same nine as the major food allergens. These allergies aren't tied to pollen, and reactions can involve the whole body, with hives, vomiting, stomach cramps or trouble breathing. MedlinePlus notes that, unlike people with these true food allergies, people with OAS rarely have severe reactions.
- Shellfish, fish, milk and eggs. OAS comes from plant foods: raw fruits, vegetables and some nuts, per the ACAAI. A reaction to shellfish or another animal food points to a different food allergy, and the ACAAI lists fish and shellfish among the most common food allergies in adults.
- Peanuts and tree nuts. These can fall on both sides. They can cause OAS in people with birch pollen allergy, but the AAAAI warns that an itchy mouth from nuts may be the first sign of a more serious nut allergy (see the food list below).
- Wheat and gluten. Wheat allergy is one of the nine major allergens. The ACAAI's wheat allergy page lists hives, stomach symptoms and, less often, anaphylaxis. Celiac disease is something else: a digestive and immune disorder that damages the small intestine when a person eats gluten, according to the NIDDK. The ACAAI says there's no such thing as a gluten allergy, and that the term usually gets confused with wheat allergy or celiac disease. Neither condition is OAS, and grains don't appear on the oral allergy syndrome lists.
- Food intolerance. Some reactions to food aren't allergies at all. MedlinePlus says a food intolerance usually means heartburn, cramps, belly pain or diarrhea after foods such as dairy, and that true food allergy is much less common. Stomach symptoms can come from a real food allergy too, though. The ACAAI says adults sometimes mistake food allergy vomiting or diarrhea for the flu or food poisoning.
If a food gives you anything beyond a brief itchy mouth, an allergist can sort out which kind of reaction it is.
Oral allergy syndrome food list
These are the oral allergy syndrome foods named by the AAAAI's pollen and food chart and OAS page, plus a few additions from other sources, marked below. The pollen linked to each food is in parentheses. You won't react to every food on your pollen's list, and some people react to only one.
Fruits
- Apple, apricot, cherry, pear, plum (birch)
- Peach (birch, grass)
- Kiwi (birch)
- Avocado (birch)*
- Pineapple‡
- Orange, tomato (grass)
- Cantaloupe, honeydew (ragweed, grass)
- Watermelon (grass, ragweed)
- Banana (ragweed)
Vegetables
- Carrot (birch, mugwort*)
- Celery (birch, grass, mugwort*)
- Parsley (birch, mugwort)
- White potato (grass, ragweed)
- Cucumber, zucchini (ragweed)
- Bell pepper, broccoli, cabbage, cauliflower, chard, garlic, onion (mugwort)
- Parsnip (mugwort)*
Nuts, seeds and legumes
- Almond, hazelnut (birch)
- Peanut, soybean (birch)
- Sunflower seeds (ragweed)†
The AAAAI warns that an itchy mouth from peanuts, soy, almonds or hazelnuts can be the first sign of a more serious food allergy. See an allergist if it happens.
Spices
- Aniseed, caraway, coriander, fennel, black pepper (mugwort)
- Mustard (mugwort)*
* From Cleveland Clinic. † From the ACAAI. ‡ From MedlinePlus, which doesn't name the pollen. Every other pairing comes from the AAAAI.
Oral allergy syndrome chart
This oral allergy syndrome chart groups the same foods by pollen, with the season when each pollen is in the air, based on the AAAAI chart plus the additions marked in the list above.
| Pollen | Season | Foods that may cause mouth symptoms |
|---|---|---|
| Birch (tree) | Spring | Apple, apricot, cherry, peach, pear, plum, kiwi, avocado, carrot, celery, parsley, almond, hazelnut, peanut, soybean |
| Timothy and orchard grass | Summer | Peach, orange, tomato, watermelon, cantaloupe, honeydew, white potato, celery |
| Ragweed (weed) | Late summer to fall | Banana, cantaloupe, honeydew, watermelon, cucumber, zucchini, white potato, sunflower seeds |
| Mugwort (weed) | Fall | Bell pepper, broccoli, cabbage, carrot, cauliflower, chard, celery, garlic, onion, parsnip, parsley, aniseed, caraway, coriander, fennel, black pepper, mustard |
If testing has shown which pollen you react to, start with that row. Our ragweed allergy guide and Seasonal Allergies by Season cover when each pollen is in the air.
Oral allergy syndrome symptoms, including rash
Oral allergy syndrome symptoms usually start within minutes of eating foods your body reacts to. The AAAAI says that in rare cases they begin more than an hour later. Typical signs:
- Itching or tingling of the lips, mouth, tongue or throat
- Mild swelling of the lips or tongue
- An itchy, scratchy throat, and sometimes itchy ears (ACAAI)
The symptoms usually fade quickly once you swallow or spit out the food, according to the ACAAI. The AAAAI says they often get worse during your pollen's season.
What about a rash? An oral allergy syndrome rash is usually small and limited to skin the raw food touched. Cleveland Clinic lists bumps on the lips or mouth, and itching, redness or swelling of the skin when you touch certain raw foods, such as on your hands while peeling or cutting them. The ACAAI says hives on the mouth are sometimes reported. Hives that spread over your body are a different matter. The AAAAI treats hives, vomiting or trouble breathing after raw produce as a whole body reaction, and MedlinePlus lists hives as a key sign of food allergy. See a doctor about any reaction that goes past your mouth and the skin the food touched.
Oral allergy syndrome diet
Because OAS reacts to the raw form of a food, an oral allergy syndrome diet usually means eating that food cooked, canned or peeled instead of raw, rather than cutting it out completely. Don't experiment on your own with a food that has bothered you. Cleveland Clinic advises avoiding foods you might be allergic to until you talk to an allergist, who can tell you which foods are safe to keep.
- Skip the raw form of foods that bother you. Avoiding the trigger food raw is the main approach, per Cleveland Clinic.
- Cook, bake or microwave it. High heat breaks down the proteins involved, the AAAAI says. Cleveland Clinic notes that even microwaving fruit for at least 10 seconds may help.
- Choose canned or processed versions. Canned food may limit reactions, the AAAAI says, and Cleveland Clinic notes that sauces and pasteurized juices are usually fine.
- Peel it. The AAAAI says the problem protein is often concentrated in the skin, so peeled fruit may cause fewer symptoms.
- Plan around foods you can't cook. Melons are usually eaten raw, so the ACAAI notes that some people simply avoid them.
- Note which varieties bother you. Some people react to only certain kinds of apples, the AAAAI says.
- Don't rely on these tips for nuts, peanuts or soy. The cooking advice above comes from guidance on fruits and vegetables. For nuts and legumes, the AAAAI says an itchy mouth may be an early sign of a more serious allergy, and the ACAAI calls peanuts and tree nuts high risk foods. Ask an allergist before eating, in any form, a nut or legume that has made your mouth itch.
Oral allergy syndrome treatment
There's no specific oral allergy syndrome treatment beyond avoiding the raw trigger foods, Cleveland Clinic says. Mild symptoms usually pass on their own, and the ACAAI says treatment usually isn't needed for them. Taking allergy medicine every day might lower reactions for some people, according to Cleveland Clinic.
Diagnosis starts with your history. The AAAAI says there's no single test for OAS, but people with it often test positive to a pollen on a skin or blood test. Our guide to allergy skin tests vs. blood tests explains the difference.
Some people need an emergency plan. The ACAAI says an allergist may prescribe an epinephrine auto injector if you've had significant throat discomfort or trouble swallowing, a reaction beyond your mouth, symptoms from cooked foods, or a reaction to peanuts or tree nuts.
Can allergy shots or ILIT help oral allergy syndrome?
They may, but that's not the main reason to try them. The AAAAI says some studies have shown allergy shots can improve OAS symptoms. A 2024 systematic review of birch pollen immunotherapy (10 studies, 475 patients) found the research too limited and uneven for firm conclusions about food symptoms. So treat the pollen allergy for its own sake, for the sneezing and itchy eyes, and count any change in your mouth symptoms as a possible bonus.
Allergy medicine controls hay fever while you take it. To change the allergy itself, these are the longer term options:
- Allergy shots (SCIT) have the longest track record. The AAAAI describes shots once or twice a week for four to six months, then every two to four weeks for three to five years. Our allergy shots guide explains the process.
- Allergy drops or tablets (SLIT) dissolve under the tongue at home, usually daily.
- ILIT (intralymphatic immunotherapy) is the shortest course, and for some people a faster alternative to allergy shots. An allergist injects FDA approved allergen extract into a lymph node in the groin (just below the waist, near the hip), guided by ultrasound. That route is an off label use of the extract. The 2008 trial that established ILIT gave three injections over two months for grass pollen allergy, compared with 54 shots over three years.
ILIT research is promising but smaller than for allergy shots, and results vary. We found no study of ILIT for oral allergy syndrome specifically, so ask any practice what it has seen in patients like you. Our comparison of allergy shots, allergy drops and ILIT sets the options side by side, and the Learn page answers whether ILIT is safe and whether it's FDA approved.
If you want to ask about a fast allergy treatment course for the pollen allergy behind your OAS, find an ILIT provider near you.
Frequently Asked Questions
It can for some people. Cleveland Clinic says there's no cure, but it can go away or improve, and some people get used to foods that once caused reactions. Keeping your seasonal allergies under control may help too, since reactions tend to be worse during your pollen season.
The most common triggers are raw fruits and vegetables tied to birch pollen. The ACAAI lists apple, almond, carrot, celery, cherry, hazelnut, kiwi, peach, pear and plum. Grass, ragweed and mugwort pollen have their own lists, shown in the chart above.
Yes, it's a real allergic reaction, though experts file it differently. The AAAAI calls it a generally mild form of food allergy. The ACAAI describes it as a pollen allergy whose symptoms happen to come from food. Either way, the AAAAI says a reaction to cooked produce or to nuts is a reason to see a doctor, since nut symptoms may signal a more serious allergy.
No. In an autoimmune disease, the immune system attacks the body's own healthy tissue by mistake, as MedlinePlus explains. In oral allergy syndrome, the immune system reacts to a protein in food because it looks like a pollen protein, which Cleveland Clinic calls cross reactivity. It's an allergy, not an attack on your own body.
Not directly. The AAAAI says there's no definitive test, but people with it often test positive to a pollen on a skin or blood test. Your symptom history ties the two together. Cleveland Clinic adds that an allergist may also use a food challenge test.
They can. Cleveland Clinic lists avocado among the foods linked to birch pollen, and MedlinePlus names pineapple among the fruits whose proteins resemble pollen proteins. Neither appears on the AAAAI's chart, so if one bothers you, tell your allergist which food it was and whether it was raw.
Usually not. Cleveland Clinic says symptoms tend to stay in the mouth and throat because stomach acid breaks the allergens down, though some people get nausea. Vomiting after raw produce is different. The AAAAI counts it as a whole body reaction that calls for a doctor's visit.
The day to day treatment is skipping the raw form of foods that bother you, and an allergist may prescribe an epinephrine auto injector if your reactions go beyond the mouth (ACAAI). For the pollen allergy behind it, immunotherapy is the longer term option, and ILIT is the shortest course, about three injections over about two months. If you'd like to ask an allergist about ILIT, use Find a Provider on OpenAirAllergyNetwork.com to locate an allergist who offers it.
