If you see a perfect apple at a farm stand, do you eagerly buy it? Or do you pass it by because you’re afraid you’d get an itchy mouth or throat after your first bite? If you’re in the second group, you may have oral allergy syndrome (OAS).

OAS results from a pollen allergy and may also be called pollen-food allergy syndrome. MyFoodAllergyTeam members often express confusion about what this condition is and how it will affect them.

“What on earth is oral allergy syndrome, and why does it matter?” one member asked. Another said, “Can I find out if anyone seriously knows anything about oral allergy syndrome? How serious is it? How much do I need to strip out of my diet to stop reactions?”

Read on to find out what OAS may mean for you and how it’s related to environmental allergens, as well as to learn more about OAS symptoms and treatment.

What Is Oral Allergy Syndrome?

OAS happens when you eat a fruit or vegetable or an herb that contains proteins similar to those in pollen. Your body may mistakenly react as if you’ve been exposed to the pollen allergen, even though you haven’t. This can be referred to as cross-reactivity.

OAS is more common than any specific food allergy, affecting 47 percent to 70 percent of people who are allergic to pollen.

For most people with OAS, cooked fruits and vegetables don’t cause an allergic reaction. Cooking changes the protein characteristics of the food. Pickling may also have an effect — some people can eat pickles but have an OAS reaction if they eat cucumbers.

For most people, the discomfort from OAS is brief and mild because stomach acid eliminates the food’s proteins. This keeps the allergic reaction from spreading.

Which Foods May Trigger an Oral Allergy Syndrome Reaction?

Different foods are linked to different allergens, so the ingredients that trigger your OAS symptoms are probably linked to your environmental allergy. Not all people with OAS react to all the foods associated with their allergies. Some of the more common allergens and their cross-reactive foods are listed below.

• Ragweed — Melons, cucumbers, bananas, zucchini, artichokes, and chamomile tea
• Birch trees — Peaches, pears, apples, cherries, nectarines, plums, prunes, kiwifruit, carrots, celery, parsley, peppers, potatoes, parsnips, hazelnuts, almonds, peanuts, soybeans, and walnuts
• Grass — Peaches, melons, oranges, tomatoes, potatoes, and Swiss chard
• Mugwort — Mustard, garlic, parsley, coriander, fennel, caraway seeds, onions, peppers, cabbage, carrots, broccoli, parsnips, and cauliflower

What Are the Symptoms of Oral Allergy Syndrome?

If you’re experiencing an OAS reaction, the symptoms may seem similar to another type of food allergy at first. Symptoms may include:

• Itching, tingling, or swelling in your mouth, lips, tongue, or throat
• Sore or scratchy throat
• Hives on your mouth or lips

In rare cases, OAS symptoms may be severe and can even cause anaphylaxis — a life-threatening, severe allergic reaction to a particular allergen. Symptoms that indicate you may be having an anaphylactic reaction include:

• Trouble breathing or shortness of breath
• Swelling or tightness in your throat
• Rapid heart rate
• Cough or wheezing
• Dizziness
• Difficulty talking
• Confusion
• Slurred speech
• Nausea, vomiting, or diarrhea
• Blue, gray, or pale lips, tongue, or skin
• Abdominal pain or cramps

If you experience anaphylaxis, immediately use your emergency food allergy medications, such as an epinephrine auto-injector like Epipen or Auvi-Q. Then call 911 for emergency medical care.

Most people don’t experience anaphylaxis from OAS, but it’s important to work with your allergist to determine how severe your condition is.

How Is Oral Allergy Syndrome Treated?

The best way to manage OAS is to avoid the food that causes your reaction. “I have oral allergy syndrome, and my tongue will swell a little,” one MyFoodAllergyTeam member wrote. “When I feel it, I immediately stop eating that food.”

You may also be able to avoid an OAS reaction by eating the allergen in cooked form and avoiding raw fruits and vegetables that trigger your symptoms. Some people find that they can avoid symptoms by peeling the skin from the offending food or trying different varieties. For instance, if an empress peach causes symptoms, a Madison peach may not.

Because OAS symptoms are rooted in environmental allergies, you may wonder whether allergy shots (immunotherapy) may help you manage OAS. For instance, if eating a banana causes your symptoms, it may seem logical that shots to prevent ragweed allergies would eliminate that reaction. Some people have reported that immunotherapy reduces their OAS symptoms, but not everyone finds that it helps.

Always keep emergency allergy medications with you in case you have a serious reaction. In addition to carrying an epinephrine injector, you might consider having over-the-counter antihistamines handy for less serious reactions.

Speak With Your Doctor

Be sure to talk with your doctor if you have a reaction to any food. Your health care provider can perform allergy tests to evaluate whether you’re allergic to the food itself or if you’re experiencing OAS. They can also advise you on how to treat and prevent symptoms.

Talk With Others Who Understand

MyFoodAllergyTeam is the social network for people with food allergies and their loved ones. On MyFoodAllergyTeam, more than 41,000 members come together to ask questions, give advice, and share their stories with others who understand life with allergies to food.

Have you ever been told you have oral allergy syndrome? What triggers your OAS? Share your experience in the comments below, or start a conversation by posting on your Activities page.