What is Oral Allergy Syndrome?  

Noticed an itching in your throat or on your lips after eating certain fruits, vegetables or nuts? It’s possible that you may have oral allergy syndrome (OAS), also known as pollen food syndrome.  

Fortunately, it’s relatively easy to manage. We’ll walk you through what foods to avoid, which allergy treatments you should consider, and how Chemist4U can help. 

Three key takeaways 

• Oral allergy syndrome is fairly common, affecting around 2% of the UK population. Symptoms include swelling lips, an itchy throat or, in rarer cases, a stomachache. 
• OAS is subtly different to a food allergy and is seen in those with a sensitivity to grass, weed or, most usually, tree pollen.  
• It can be easily managed using allergy treatments, preparing food differently, and avoiding triggers.  

What causes oral allergy syndrome?  

“Although you might notice symptoms immediately after eating certain fruits, nuts or vegetables, oral allergy syndrome is usually linked to an allergy to pollen (or sometimes latex) rather than the food you’ve eaten. Your body is just confusing your pollen allergy with signals given by some foods.  

“This is because those fruits, nuts and vegetables contain proteins that 'look' like those in some pollen or latex, causing confusion. Your lips, throat, stomach, or ears react to those signals by becoming irritated and swelling or itching. 

“In the UK, oral allergy symptoms tend to be worse from March to May, which is when birch pollen is in season.” 

Hanna Yusuf, Prescribing Pharmacist at Chemist4U 

Who is affected by oral allergy syndrome?  

People who are affected by oral allergy syndrome have seasonal pollen allergies. In the UK, it’s most common in those allergic to birch pollen. 

Some people are allergic to one kind of food, while others are sensitive to a wider variety. Most reactions are to raw food, but cooked celery and nuts can cause reactions.  

What’s the difference between oral allergy syndrome and a food allergy?  

Oral allergy syndrome is not the same as a food allergy. Key differences include:  

	Oral allergy syndrome	Food allergies
Symptoms	Irritation in lips, tongue, mouth, throat, nose or ears.  Very uncommonly hives, stomach irritation, anxiety or anaphylaxis.	Hives, vomiting, diarrhoea, breathing difficulties, and anaphylaxis.
Severity of symptoms	Usually mild and short-lived.	Can be more serious and even life-threatening.
Speed of appearance of symptoms	Immediate	Immediate or delayed.
Symptoms reduced if food is cooked.	Usually.	Not always.
Cause	Cross-reaction to pollen or latex.	Direct reaction.

Symptoms of oral allergy syndrome  

Common symptoms of oral allergy syndrome can include:  

• itching and swelling lips, tongue, mouth, ears or throat  
• eye and skin irritation 
• sneezing when preparing food  

Rarer symptoms include:  

• nausea  
• vomiting  

Very rare symptoms include:  

• breathing difficulties 

How quickly do symptoms appear?  

Symptoms usually appear within five to 10 minutes of eating the food that causes the reaction, and, without treatment, disappear within an hour.  

When to seek medical help  

If your symptoms change you should speak to your GP.  

Seek urgent medical attention in hospital, or call 999 if:  

• your lips, mouth, throat or tongue suddenly become swollen 
• your breathing rate increases rapidly or you feel wheezy 
• you are struggling to swallow 
• you become drowsy, confused or dizzy  
• your lips become pale or turn blue or grey 
• someone has fainted  
• a child becomes floppy or limp 

Foods that can cause oral allergy syndrome  

Each pollen allergy is linked to certain foods. While this table gives general guidance, always consult your GP if you’re not sure whether your symptoms are linked to oral allergy syndrome or a food allergy. 

Type of allergy	Vegetables	Fruit	Seeds, herbs and spices	Nut
Birch and alder pollen	Celery, bean sprouts, carrot, mange tout, green pepper, potato, soya, tomato, parsnip, peas	Apple, apricot, cherry, coriander, kiwi, nectarine, parsley, peach, pear, plum, strawberry	Basil, coriander, fennel, oregano, parsley, paprika, pepper, thyme	Almond, brazil nut, hazel, walnut
Grass pollen	Potato, swiss chard, tomato, peas	Kiwi, melon, orange, watermelon, date	Wheat	Peanut
Ragweed pollen	Artichoke,  cucumber, courgette	N/A	Sunflower, echinacea, chamomile	N/A
Mugwort and other weed pollen	Celery, carrot, green pepper, onion	Apple, banana, melon, orange, peach, tomato, watermelon	Sunflower seed, aniseed, celery salt, mustard, spices, coriander, fennel, parsley	N/A
Latex	Peppers, celery	Avocado, mango, grape, banana, plum, kiwi, melon, papaya, citrus, pineapple	N/A	Chestnuts

How is oral allergy syndrome diagnosed?  

Usually, a doctor will diagnose pollen food syndrome from a consultation. But if it’s not clear whether you have oral allergy syndrome or food allergies, you will be referred to a clinic for more blood or skin prick testing.  

Skin prick testing involves putting a small amount of the allergen onto your skin and then using a lancet to prick through the drop to allow a very small amount of the allergen into the skin. If you’re sensitised to that allergen, you’ll notice that patch of skin becoming itchy or bumpy.  

How to treat oral allergy syndrome  

If you experience a new reaction to a fruit or vegetable, immediately rinse your mouth with water. 

Allergies can be managed by taking antihistamines, either when you notice symptoms, or daily during high pollen season.  

6 tips for managing oral allergy syndrome  

Oral allergy syndrome is easily managed. Here are six simple steps to help control your symptoms:  

1. Avoiding trigger foods when you can, especially during high pollen season.  

2. Cooking fruits, nuts or vegetables that cause symptoms.  

3. Peeling fruits or vegetables that cause symptoms.  

4. Wearing gloves or safety glasses when preparing foods you know cause symptoms.  

5. Taking antihistamine treatments like cetirizine, loratadine, or fexofenadine to treat the underlying pollen allergy. 

6. Keeping a food diary so you know which fruits, vegetables or seeds might be triggering your allergy.  

How Chemist4U can help 

Although there’s no cure for pollen food allergy syndrome, we have a range of allergy treatments to help you manage your symptoms. 

Some are available without prescription, while others require a consultation with our experienced clinicians. 

There’s something suitable for all the family, including antihistamines, syrups and eye drops. We can even help you restock your EpiPen if your doctor has prescribed one for potentially serious symptoms.  

Frequently asked questions about oral allergy syndrome  

Why did I suddenly develop oral allergy syndrome?  

Oral allergy syndrome is unpredictable! It’s likely that you have an underlying allergy to grass or tree pollen or latex, and your body has started to mistake certain foods for that pollen or latex. Pollen food allergy syndrome starts when your immune system becomes sensitised enough to trigger a reaction to those foods. For some, that starts in childhood, but it can become a problem at any point in your life.  

What can be mistaken for oral allergy syndrome?  

It’s possible to mistake food or latex allergy symptoms for oral allergy syndrome, as the symptoms are very similar. If you’re at all unsure about which form of allergy you have, you should see your GP. Some people also mistake their symptoms for allergies to pesticides  

Does oral allergy syndrome go away?   

No, the syndrome rarely disappears on its own, but it is usually mild and easily manageable. It often gets worse during peak pollen season.  

Sources  

• Food Allergy (2026). NHS [Accessed 6th February 2026].  
• Oral Allergy Syndrome (Pollen Food Syndrome) (2026). Allergy UK [Accessed 6th February 2026]. 
• Pollen food allergy syndrome (PFAS): A review of current available literature (2019). Annals Of Allergy Asthma and Immunology [Accessed 6th February 2026]. 
• Ragweed Allergies 2026. Allergy & Asthma Network [Accessed 6th February 2026]. 
• Pollen Food Syndrome. Oxford University Hospitals [Accessed 6th February 2026]. 
• Oral Allergy Syndrome (OAS) . Stanford Medicine [Accessed 6th February 2026]. 
• Oral allergy syndrome (OAS) (2025). Sheffield Children’s NHS Trust [Accessed 6th February 2026].