Oral Allergy Syndrome (OAS) is a common allergic condition that primarily affects individuals with pollen allergies. It occurs when the immune system mistakes proteins in certain raw fruits, vegetables, and nuts for pollen proteins, triggering an allergic reaction in the mouth, lips, throat, or tongue. Though usually mild, symptoms can be uncomfortable and confusing for many sufferers.
In this blog, we’ll explore the causes, signs, foods to avoid, treatment strategies, and when to seek emergency care.
What is Oral Allergy Syndrome?
Oral Allergy Syndrome is also known as pollen-food allergy syndrome. It primarily affects individuals who are already allergic to pollen, such as birch, ragweed, or grass. When these individuals consume certain plant-based foods, the immune system reacts as though it’s encountering pollen, causing an allergic reaction localized to the mouth and throat.
OAS typically affects teens and adults with established pollen allergies. It is estimated that up to 70% of people with pollen allergies experience OAS symptoms at some point.
Causes of Oral Allergy Syndrome
OAS is caused by cross-reactivity between pollen proteins and similar proteins found in specific fruits, vegetables, and nuts. When a person is allergic to a certain type of pollen and consumes these foods, the immune system misidentifies the food protein as a harmful allergen, leading to an allergic reaction.
The primary pollens linked to OAS include:
- Birch tree pollen
- Grass pollen
- Ragweed pollen
- Mugwort and other weeds
This cross-reactivity is why symptoms tend to occur during pollen seasons, although they can also happen year-round depending on diet and exposure.
Symptoms of Oral Allergy Syndrome
Symptoms of OAS typically occur immediately after eating raw fruits, vegetables, or nuts. These symptoms are usually mild and resolve on their own within 30 minutes to 1 hour.
Common OAS symptoms include:
- Itchy or tingling lips, mouth, and throat
- Swelling of the lips, tongue, or throat
- Scratchy throat or mild hoarseness
- Watery eyes or sneezing (in some cases)
Severe symptoms are rare but may include difficulty breathing or swallowing. In such cases, seek immediate emergency care.
Complete List of Foods Linked to Oral Allergy Syndrome
Here’s a comprehensive list of OAS-triggering foods, grouped by the type of pollen they cross-react with:
Birch Pollen Cross-Reactive Foods:
- Apples
- Pears
- Cherries
- Peaches
- Plums
- Apricots
- Carrots
- Celery
- Hazelnuts
- Almonds
- Kiwi
Ragweed Pollen Cross-Reactive Foods:
- Bananas
- Cucumbers
- Zucchini
- Melons (watermelon, cantaloupe, honeydew)
- Sunflower seeds
Grass Pollen Cross-Reactive Foods:
- Oranges
- Tomatoes
- White potatoes
- Peppers
- Peaches
- Melons
Mugwort Pollen Cross-Reactive Foods:
- Celery
- Carrots
- Parsley
- Coriander
- Fennel
- Peppers
- Aniseed
- Sunflower seeds
It’s important to note that cooking or peeling fruits and vegetables often destroys the offending proteins, making them safe to eat.
Diagnosing Oral Allergy Syndrome
Diagnosing OAS typically involves a medical history review and allergy testing. An allergist may perform skin prick tests or blood tests to identify pollen allergies and confirm the cross-reactivity with food allergens.
In many cases, patients can self-report patterns of symptoms after consuming specific raw foods during allergy season, which can guide diagnosis without extensive testing.
Treatment of Oral Allergy Syndrome
There is no cure for OAS, but symptoms can often be managed through a combination of lifestyle changes and medical treatment. Most reactions are mild and self-limiting.
Treatment Options:
- Avoid raw trigger foods during pollen season or year-round if symptoms are persistent.
- Cook or peel fruits and vegetables to reduce allergic protein exposure.
- Take antihistamines before meals that may include problem foods.
- Allergy shots (immunotherapy) may reduce overall pollen sensitivity and indirectly ease OAS symptoms.
If symptoms worsen or become systemic, an epinephrine auto-injector (EpiPen) may be recommended.
Preventive Tips for People with OAS
Prevention starts with awareness of your triggers and modifying your diet accordingly. Keeping a food diary can help identify patterns and reduce exposure.
Here are a few tips:
- Eat cooked versions of trigger foods when possible.
- Avoid raw versions of fruits/vegetables known to cause symptoms.
- Be cautious when trying new fruits or vegetables, especially during allergy season.
- Consult an allergist before reintroducing suspected foods.
When to Seek Emergency Care
Although OAS is usually mild, rare cases can escalate into a more serious reaction like anaphylaxis. Be alert to the following warning signs:
- Difficulty breathing or shortness of breath
- Severe swelling of the face, lips, or tongue
- Rapid heartbeat or chest tightness
- Dizziness or fainting
If you experience these symptoms, seek emergency care immediately.
Get 24/7 Emergency Allergy Care at Altus Emergency Center
If you or a loved one experiences a severe reaction related to oral allergy syndrome or any type of allergy, visit Altus Emergency Center for expert care. Open 24/7, Altus provides immediate access to board-certified emergency physicians and state-of-the-art equipment to handle allergic reactions safely and swiftly.
Whether it’s OAS symptoms that won’t subside or a life-threatening allergic episode, trust Altus Emergency Center to deliver timely, compassionate, and effective treatment, day or night.
Altus Emergency Center: Always Open. Always Ready.