Have you ever eaten a fresh piece of fruit and felt your mouth tingle or itch afterward? You may have experienced oral allergy syndrome (OAS). This condition can turn your favorite fruits, vegetables and nuts into unexpected irritants.
The good news is that OAS is usually more bothersome than serious. Read on to find out about this common condition – how to identify and treat OAS and why you might develop symptoms.
What is oral allergy syndrome?
Oral allergy syndrome (OAS), also known as pollen-food allergy syndrome, is an allergic reaction to the proteins in certain raw fruits, vegetables or tree nuts.
“The proteins in some fresh fruits, vegetables and tree nuts are similar to those in pollens,” said Samia Kadri, a family nurse practitioner with Banner Urgent Care. “OAS occurs because your immune system mistakes proteins in certain raw foods for pollen proteins. When these foods touch your mouth and throat, it can cause allergic symptoms.”
Often, a person with OAS can eat the same food when it’s cooked or peeled, and it will not trigger the same reaction. More on that in a bit.
Am I at risk for an oral allergy syndrome?
“OAS is common in adults, especially those with pollen allergies,” Kadri said. “It is the most common food allergy in adults.”
If you have hay fever (allergic rhinitis) or asthma caused by specific pollens, such as birch, grass or ragweed, your body may react to certain food proteins as well.
While OAS mostly affects adults, people can develop the allergy at any point in their lives, including after years of eating the same food without a reaction.
What foods should I avoid with oral allergy syndrome?
Raw, uncooked fruit, vegetables and some nuts are the main foods that cause OAS. Different types of pollen are linked to different foods.
Here are some of the most common pollen food cross-reactions:
Birch pollen (spring)
Fruit: apples, apricots, avocadoes, cherries, kiwis, nectarines, peaches, pears, pineapples
Vegetables: carrots, celery, parsley
Legumes: peanuts, soybeans
Herbs: caraway, coriander, fennel
Nuts: almonds, hazelnuts
Grass pollen (summer)
Fruit: oranges, peaches, tomatoes, melons (watermelon, cantaloupe, honeydew)
Vegetables: white potatoes, Swiss chard
Ragweed pollen (late summer-fall)
Fruit: apples, bananas, melons (watermelon, cantaloupe, honeydew)
Vegetables: artichokes, cucumbers, white potatoes, zucchini
Nuts: sunflower seeds
Mugwort (fall)
Vegetables: bell peppers, broccoli, cabbage, carrots, cauliflower, onion, parsley
Herbs: aniseed, caraway, coriander, fennel, garlic
Other oral allergies include berries, grapes, mangoes and pomegranates.
Only foods that come from plants cause OAS. “Animal-source foods like milk, eggs or seafood are non-plant foods and do not contain proteins that resemble pollens,” Kadri said.
What are the symptoms of oral allergy syndrome?
When you have OAS, your body reacts to the food in a similar way it would to pollen. Symptoms usually appear quickly after eating.
They include:
- Itchy or tingling mouth and throat
- Mild swelling of the lips, tongue or throat
- Scratchy throat
- Sneezing and stuffy nose (nasal congestion)
Less common symptoms may include stomach pains, nausea, hives or rash.
“Symptoms usually appear five to 10 minutes after eating and usually go away minutes after eating,” Kadri said. “People with OAS generally won’t have a severe allergic reaction or anaphylaxis.”
That said, she encourages anyone who experiences symptoms such as trouble breathing, sudden chest pain, swelling of the tongue and throat or anaphylaxis to seek emergency medical help immediately.
What to do if you suspect you have OAS
If you think you have OAS symptoms, note when they happen and after eating which foods. Share these notes with an allergist.
“It is best to see an allergist to differentiate between pollen food allergies and other systemic allergies,” Kadri said. “They can confirm the diagnosis and help you manage the condition.”
There’s no specific test for OAS, but an allergist may use the following tests and challenges:
- Skin prick test: The allergist puts a small amount of the allergen (like pollen) on your skin, usually your forearm or back. The skin is then pricked so the allergen can enter just below the surface. If you’re allergic, you’ll get a raised bump at the test site.
- Blood test: This involves analyzing your blood for immunoglobulin (IgE) antibodies. These allergy-related antibodies fight against allergens like pollen, raw fruit and vegetables. Higher amounts can be a sign that your body is overreacting to allergens.
- Food challenge: In some cases, your provider might give you an increasing number of certain foods to see if you have signs of an allergic reaction.
Tips for living with oral allergy syndrome
While there’s no universal remedy to cure OAS, there are several ways to make life easier when you have this condition:
- Avoid the food: The simplest way to manage OAS is to avoid raw foods that cause symptoms.
- Try alternatives: If raw fruit and vegetables trigger your OAS, try eating them canned, cooked, dried or peeled. Cooking often breaks down the proteins that cause OAS. You can also try peeling fruit and vegetables, as the peels often contain most of the protein that causes the allergic reaction.
- Take allergy medication: Over-the-counter (OTC) antihistamines can help manage mild symptoms. If you have a severe reaction, your provider might prescribe an epinephrine autoinjector (like an EpiPen). If you are prescribed an EpiPen, carry it with you at all times and know how to use it.
- Try immunotherapy: In some cases, your provider may recommend allergy shots or allergy drops (sublingual immunotherapy). Allergen immunotherapy involves giving small amounts of allergens through injections or placing them under the tongue over months or years. This process trains your immune system to react less over time.
Conclusion
Oral allergy syndrome (OAS) is a common condition for people with seasonal allergies. The next time you eat raw fruit and vegetables, don’t be alarmed if you notice itching or tingling in your mouth.
If you suspect you have OAS, see an allergist or a Banner Health specialist to get a proper diagnosis and treatment plan. With informed choices and some minor changes to your eating habits, you can enjoy meals without itching for relief.
