Why do I still experience oral allergy syndrome reactions to raw foods even if they are not cooked, should I get re-tested for allergies?

Oral Allergy Syndrome: Understanding Reactions to Raw Foods and Need for Re-testing

You should consult with an allergist for re-testing as oral allergy syndrome (OAS) reactions to raw foods can occur even without cooking due to the cross-reactivity between pollen allergens and structurally similar proteins in fresh fruits and vegetables. 1, 2

Why You React to Raw Foods in Oral Allergy Syndrome

OAS occurs because:

• Your immune system mistakes proteins in raw fruits and vegetables for pollen allergens (cross-reactivity) 2
• The primary allergenic proteins (like Mal d 1 in apples) remain intact in raw foods 2
• These proteins trigger an IgE-mediated allergic reaction when they contact the oral mucosa 3

Unlike true food allergies that typically cause systemic reactions, OAS usually causes localized symptoms in the mouth and throat:

• Itching and swelling of lips, palate, and tongue
• Symptoms typically occur immediately after consuming fresh fruits or vegetables 4

Why Cooking Often Helps (But Raw Foods Still Cause Reactions)

• Heat from cooking denatures the allergenic proteins responsible for cross-reactions 2
• Commercial processing methods like pasteurization alter the structure of these proteins 2
• Raw foods contain intact allergenic proteins that can bind to IgE antibodies and trigger reactions 3

When to Consider Re-testing for Allergies

You should seek allergy re-testing if:

• Your symptoms have changed or worsened over time 1
• You're experiencing symptoms beyond the typical oral reactions (such as skin reactions, respiratory symptoms, or gastrointestinal issues) 5
• You want to identify specific trigger foods to better manage your condition 1
• You're unsure if your reactions are from OAS or a true food allergy 1

What to Expect During Allergy Re-testing

An allergist can perform:

1. Skin prick tests (SPT) to identify sensitization to specific pollens and foods 1
2. Serum-specific IgE testing to measure antibodies to suspected allergens 1
3. Oral food challenges under medical supervision to confirm allergies 1

Important Considerations and Precautions

• OAS is typically mild but can occasionally progress to more severe reactions 5
• Recent research shows that some patients with OAS can experience systemic reactions, especially with concentrated forms of plant foods (smoothies, juices) 5
• Avoid unpasteurized juices, which may contain intact allergens 2
• Be cautious with new forms of plant foods in your diet (smoothies, supplements) 5

Managing Oral Allergy Syndrome

Until you can see an allergist:

• Avoid raw fruits and vegetables that trigger symptoms
• Try cooking or processing trigger foods, as this often makes them tolerable 2
• Consider taking antihistamines before potential exposure if recommended by your doctor 4
• Be aware that OAS symptoms may vary seasonally, often worsening during pollen seasons 3

Remember that proper diagnosis is essential, as unnecessarily restricting your diet can impact nutrition and quality of life 2. An allergist can provide personalized guidance on managing your specific condition.