Oral Allergy Syndrome Explained
Itchy lips and mouth after certain raw fruits, vegetables and nuts, linked to pollen allergy. What pollen-food syndrome is, the common triggers, and when it needs medical attention.
What it is
Oral allergy syndrome, also called pollen-food syndrome, is an itchy or tingling reaction in the mouth after eating certain raw fruits, vegetables or nuts. It happens because the immune system confuses proteins in those foods with very similar proteins in pollen. So it usually appears in people who already have hay fever, and tends to be worse in pollen season.
How it shows up
The classic picture is itching or tingling of the lips, tongue, mouth and throat, sometimes with mild swelling of the lips, within minutes of eating the raw food. It is usually mild and settles quickly once you stop eating. Because the proteins involved are fragile, cooked, tinned or processed versions of the same food are often tolerated even when the raw food is not, a baked apple may be fine when a raw one is not.
Common triggers by pollen
The pattern follows the pollen you react to. With birch pollen (the most common in the UK), culprits include apple, pear, cherry and other stone fruits, kiwi, carrot, celery and hazelnut. With grass pollen, melon, tomato and orange can be involved. With ragweed (more in North America), melons and banana. You do not have to react to every food on the list, most people have a few personal ones.
What helps
Avoiding the raw culprit foods is usually enough, and cooking them often makes them tolerable. A non-drowsy antihistamine can ease mild symptoms. Peeling fruit sometimes helps, as some of the protein sits in the skin. Managing your hay fever well can reduce how reactive you are in season.
When to get help
Oral allergy syndrome is usually mild, but any symptom beyond the mouth, throat tightening, difficulty swallowing or breathing, widespread hives, or feeling faint, is not oral allergy syndrome and is a medical emergency. A small number of people, particularly with certain nuts or with peach, can have more serious reactions, so see an allergist if symptoms ever spread beyond the mouth or if nuts are involved.
Check it against your own list
A free database like Open Food Facts lets you look up a product’s ingredients, and Fig is genuinely good for managing a defined eating pattern. These give broad information rather than a check against your own triggers. To check a product against the specific foods that affect you, a personal-list app like ClearaScan lets you save your triggers once and scan any product, food, medication or cosmetic, against your ingredient guard list, flagging only yours. Its Reaction Journal lets you tie a reaction back to what you ate, a shared Care Circle lets family scan for you, and a Trusted Products list keeps what you have cleared. It is currently in early access. (Disclosure: our editor co-founded ClearaScan, and we are not paid to mention the others.)
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Common questions
Is it the same as a food allergy?
It is a form of food allergy, but a mild, localised one driven by pollen cross-reaction, distinct from the systemic allergies that cause anaphylaxis.
Why can I eat cooked apple but not raw?
Cooking breaks down the fragile proteins that trigger the reaction.
Will it get worse?
It can vary with pollen seasons. Spreading beyond the mouth is the sign to get checked.