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Oral Allergy Syndrome: Understanding and Managing Pollen-Food Syndrome

In this blog, we will explore Oral Allergy Syndrome (OAS), a food allergy that commonly affects individuals with pollen allergies. We will explain its causes, symptoms, and how The London Allergy Clinic can help you manage it.


Hay fever

What is Oral Allergy Syndrome?


Oral Allergy Syndrome (OAS), also known as Pollen-Food Syndrome, is a type of food allergy that is triggered by consuming certain raw fruits, vegetables, or nuts.

Common culprits include apples, plums, peaches, cherries, pears, tomatoes, kiwis, peanuts, hazelnuts, and almonds, but reactions can occur with almost any fruit, vegetable, or nut.

Some people may find that their allergies are triggered only by one or two specific fruits or nuts, whilst others may experience symptoms with a wide range of foods.

 

The Pollen Connection

Oral allergy syndrome, whilst thought by many patients to be a food allergy, is in fact caused by a pollen allergy (hay fever).  It arises due to the cross-reactivity of proteins in fruits/vegetables/nuts with the proteins in pollen.  

 

Cross-reactivity is when the body mistakenly identifies the proteins within one substance (e.g a food) for the proteins within another substance (e.g a pollen) and triggers an allergic reaction as a result.   This usually happens when the proteins are similar in structure.

 

Most commonly in Europe it is Silver Birch pollen allergies which gives rise to oral allergy syndrome.  And usually it is the PR-10 proteins in particular which are responsible.

 

In the UK, around 40% of people with Silver Birch pollen allergy develop OAS, although other pollen types, such as grass or weed pollen, can also cause cross-reactivity in a similar way.

 

PR-10 proteins are sensitive to heat, meaning they are denatured when food is cooked, which is why most OAS symptoms occur only after consuming raw produce, and not cooked food.


 

Symptoms of Oral Allergy Syndrome


Symptoms of Oral Allergy Syndrome typically appear within 10 minutes of eating the offending food and can include:

·         Itching or swelling of the lips, tongue, inner mouth, throat, or ears.

·         A tingling sensation in the mouth or throat.

·         Mild swelling around the face or lips.

In most cases, these symptoms resolve within an hour.  Occasionally, more severe symptoms such as nausea, vomiting, or, very rarely, breathing difficulties can occur.

 

Managing Oral Allergy Syndrome

At The London Allergy Clinic, we specialise in diagnosing and treating a variety of allergies, including Oral Allergy Syndrome. Our highly qualified team of specialist clinicians provides expert care to help manage your symptoms and improve your quality of life.

Allergy Testing and Diagnosis

Understanding whether your food allergy is related to a pollen allergy or a more serious food sensitivity is crucial for treatment. Our clinic offers a range of tests to accurately diagnose Oral Allergy Syndrome, including:

·         Skin Prick Testing

·         Specific IgE Blood Tests

·         Molecular-Component IgE

These tests help determine which proteins are responsible for your allergic reactions, whether they are pollen-related or specific to the food itself. For example, differentiating between a PR-10-related peanut allergy (pollen related and more likely to be mild) and a sensitisation to a different peanut protein, which may be more likely to be severe, is essential for appropriate treatment.


How The London Allergy Clinic Can Help


At The London Allergy Clinic we offer a tailored approach to managing OAS. Once we’ve identified the triggers of your symptoms, we can help develop a management plan that fits your lifestyle. This might include avoiding specific raw fruits and vegetables, opting for cooked alternatives, or employing treatment therapies such as immunotherapy when necessary.

Our clinic is home to specialist clinicians with extensive experience in diagnosing and treating allergies. We work closely with our patients to create personalised care plans, ensuring that you receive the best possible treatment and support.


The ALEX Allergy Xplorer: Home Allergy Testing Kit


For those who want a comprehensive view of their allergies from the comfort of home, The London Allergy Clinic offers the ALEX Allergy Xplorer panel test. This advanced test covers 295 allergens, including:

·         Food allergens: Nuts, wheat, soya, vegetables, fruit, dairy, meat, fish, and more.

·         Environmental allergens: Pollen, house dust mites, pet allergies.

·         Mould allergies: Aspergillus, Cladosporium, Alternaria.

·         Insect allergies: Including bee and wasp venom.

The ALEX Allergy Xplorer test is the most wide-ranging allergy test currently available, that is easy to use and provides highly accurate results, helping you and your doctor identify the root causes of your symptoms. With no appointment needed, it’s a convenient option for both adults and children over the age of 1.5 years.  To learn more about this test or to order a kit, contact us here.

 

FAQs About Oral Allergy Syndrome


1. What causes Oral Allergy Syndrome?

Oral Allergy Syndrome is caused by cross-reactivity between proteins in certain foods (usually raw fruits and nuts) and pollen proteins. The immune system mistakes the food proteins for pollen, triggering an allergic reaction.


2. Can Oral Allergy Syndrome lead to a severe reaction?


In most cases, OAS symptoms are mild and limited to itching or swelling in the mouth or throat. However, in rare cases, symptoms can become more severe, requiring medical attention.


3. Can I eat cooked versions of the food that may trigger my OAS?

Usually, yes. Cooking denatures the proteins responsible for triggering OAS, making them less likely to cause an allergic reaction.


4. How is Oral Allergy Syndrome diagnosed?

OAS is typically diagnosed through a combination of your medical history, symptoms, and specific allergy tests such as skin prick testing and IgE blood tests. Find out more about our diagnostic tests.


5. How can The London Allergy Clinic help me manage OAS?


Our team of expert allergists can help diagnose and manage your condition through a personalised care plan, tailored to your specific triggers. We offer a variety of allergy tests and treatment options, including pollen desensitisation (immunotherapy). Get in touch with us today.



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