Introduction
In patients who are already allergic to pollen, eating these foods — usually raw — can trigger symptoms, mainly in the mouth and sometimes more widespread.
Symptoms
- Tingling and itching of the mouth and throat
- Mild swelling of the lips, tongue or palate
- Burning sensation in the mouth
- Rarely: urticaria, digestive symptoms
- Exceptionally: respiratory symptoms or a systemic reaction
Causes
- Prior sensitisation to pollen (birch, grasses, ragweed…)
- Shared proteins (molecular homology) between pollens and foods
- Heat-labile proteins, destroyed by cooking
- Atopic background (allergic rhinitis, asthma, eczema)
- Birch → apple, pear, hazelnut, carrot
- Grasses → tomato, melon, orange
- Ragweed → banana, melon, courgette
- Mugwort → celery, carrot, spices
Diagnosis
- Targeted history (known pollen allergies, trigger foods)
- Immediate timing of symptoms
- Skin prick tests with pollens and raw foods
- Specific IgE blood tests if needed
- Molecular (component-resolved) tests in some cases
Treatments
- Selective avoidance of the foods responsible when raw
- Cooked or peeled foods can often be eaten
- Antihistamines if symptoms are bothersome
- Optimal treatment of the associated respiratory allergy
- Adrenaline auto-injector only in specific situations
- cooked
- peeled
Management
To identify precisely which pollen–food pairs are involved
To avoid unnecessary food exclusions
To reassure you that the condition is usually benign
To adjust management during the pollen season