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Food & digestive allergies

Pollen-food allergy syndrome (PFAS)

Why do some raw foods make the mouth tingle in a person with pollen allergy?

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In this sheet

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3 essential points

Pollen and food can ‘look alike’
IgE directed against pollen may recognise similar proteins in some fruit, vegetables, tree nuts or other plants.
Most often: mouth and throat, with rapid onset
Tingling, itching or mild swelling of the lips, mouth, palate or throat often occurs with the raw food.
A reaction beyond the mouth warrants specific assessment
Generalised urticaria, breathing difficulty, feeling faint, significant vomiting or a reaction to a cooked form should not be dismissed.

Why can pollen cause a reaction to a food?

Some plant proteins have a sufficiently similar structure for the immune system to confuse them. A classic example is birch sensitisation recognising related proteins in apple, hazelnut or other plants.

This does not mean that everyone with pollen allergy will react to every ‘cross-reactive’ food.

What does a typical reaction look like?

Symptoms usually begin quickly after eating the food, often raw:

tingling or itching of the lips and mouth;
itchy palate or throat;
mild swelling of the lips or mouth;
symptoms that are often brief and mainly limited to the oropharynx.

Why raw but sometimes not cooked?

Some proteins commonly involved in PFAS, including many PR-10 proteins and profilins, are sensitive to heat and digestion. A raw food may therefore cause symptoms while a well-cooked or processed form is sometimes tolerated.

Some common associations — examples only

Pollen / profile: Birch / PR-10
Examples of foods sometimes involved: Apple, pear, peach, cherry, hazelnut, carrot, celery…

Pollen / profile: Grass pollen / profilins
Examples of foods sometimes involved: Melon, watermelon, tomato, citrus fruit… depending on the individual profile.

Pollen / profile: Mugwort / ragweed
Examples of foods sometimes involved: Some associations with celery, spices, melon or other plants, depending on sensitisation.

Pollen / profile	Examples of foods sometimes involved
Birch / PR-10	Apple, pear, peach, cherry, hazelnut, carrot, celery…
Grass pollen / profilins	Melon, watermelon, tomato, citrus fruit… depending on the individual profile.
Mugwort / ragweed	Some associations with celery, spices, melon or other plants, depending on sensitisation.

These associations are not a list of foods to eliminate. Avoid the food that actually causes a reaction, not an entire theoretical family.

Classic PFAS ≠ primary food allergy

Situation: Classic PFAS
Guidance: Pollen sensitisation, cross-reaction, often to raw food, with symptoms mainly in the mouth/throat; proteins are often labile, such as PR-10 or profilins.

Situation: Primary food allergy
Guidance: Sensitisation directed against the food itself; some proteins are more stable and may be associated with more significant systemic reactions.

Situation	Guidance
Classic PFAS	Pollen sensitisation, cross-reaction, often to raw food, with symptoms mainly in the mouth/throat; proteins are often labile, such as PR-10 or profilins.
Primary food allergy	Sensitisation directed against the food itself; some proteins are more stable and may be associated with more significant systemic reactions.

Symptoms alone do not always distinguish these mechanisms. This is particularly important with hazelnut, peanut and other tree nuts.

Why does my allergist talk about molecules?

PR-10: Often associated with birch; generally sensitive to heat and digestion; reactions are often oral.
Profilins: Widely found in pollen and plants; may explain multiple cross-reactions that are often limited.
LTP: Some lipid transfer proteins are more stable and may be associated with more significant reactions, particularly with cofactors. This is not the same as simple, mild PFAS.

What about skin-prick tests or IgE?

A positive test is not enough to decide on avoidance. In a person sensitised to pollen, cross-reactions may make some tests positive without proving a clinically significant food allergy.

See also: ‘Skin-prick tests’ and, where appropriate, molecular assessment explained by your allergist.

When might this not be mild PFAS?

Request reassessment if you have experienced:

generalised urticaria or marked swelling;
breathing difficulty, change in voice or feeling faint;
significant vomiting or marked digestive symptoms;
a reaction to a very small amount or also to a cooked form;
an unusual reaction to peanut or tree nuts;
a reaction promoted by exercise, NSAIDs or alcohol;
poorly controlled asthma or a history of a severe reaction.

In a severe reaction

Follow your personalised emergency plan. If an adrenaline auto-injector has been prescribed for anaphylaxis, use it according to that plan and call 15 or 112.

Frequently asked questions and daily life

Smoothies, juices and large quantities

A large smoothie or juice can quickly provide a substantial amount of raw food. In some patients, this exposure is not equivalent to a few bites eaten slowly and may promote more significant symptoms.

Cofactors

Exercise, NSAIDs such as ibuprofen or aspirin, and alcohol may increase the likelihood or intensity of a food reaction in some patients. This does not justify systematically prohibiting them in everyone with PFAS.

See ‘Exercise-induced anaphylaxis and cofactors’.

Does everyone with PFAS need adrenaline?

No. An auto-injector is not automatically required for classic PFAS limited to the mouth. The decision depends on the clinical history, any symptoms beyond the oropharynx and individual risk factors.

If an emergency plan with adrenaline has been prescribed, it takes priority.

Is an oral food challenge (OFC) needed?

Not routinely. The history may be highly suggestive. If there is doubt, to distinguish PFAS from another food allergy or verify tolerance, the allergist may suggest further tests and sometimes a supervised OFC.

See ‘Challenge tests: oral food and drug challenges’.

Does pollen immunotherapy treat PFAS?

Allergen immunotherapy may be indicated for allergic rhinitis or asthma when the criteria are met. PFAS alone, however, is not an established indication for pollen immunotherapy, and its effect on food reactions remains uncertain.

Can I continue a food that only causes mild tingling?

There is no rule that applies to everyone. When reactions have always been mild and strictly limited to the mouth, the allergist can clarify which forms should actually be avoided and whether some cooked or processed forms are tolerated.

Does pollen season change reactions?

Some people report more food symptoms during their pollen season, but this observation is not reliable enough to determine avoidance or reintroduction on its own. Record any seasonal pattern and discuss it with your allergist.

Common misconceptions

Misconception: ‘I am allergic to birch, so I must avoid all apples, hazelnuts, peaches and carrots.’
SOS Allergo response: No. Do not remove tolerated foods based on a theoretical list of cross-reactions.

Misconception: ‘My hazelnut test is positive, so it must be simple PFAS.’
SOS Allergo response: No. Cross-reaction sometimes needs to be distinguished from primary allergy.

Misconception: ‘If I tolerate a cooked food, I can always eat it cooked.’
SOS Allergo response: Not always. It depends on the food and proteins involved.

Misconception: ‘PFAS reactions are always mild.’
SOS Allergo response: Most are mild and oral, but more significant reactions are possible.

Misconception: ‘Everyone with PFAS needs adrenaline.’
SOS Allergo response: No. The decision depends on your history and risk level.

Misconception: ‘Pollen immunotherapy will cure my food allergy.’
SOS Allergo response: This benefit has not been demonstrated reliably enough.

Misconception	SOS Allergo response
‘I am allergic to birch, so I must avoid all apples, hazelnuts, peaches and carrots.’	No. Do not remove tolerated foods based on a theoretical list of cross-reactions.
‘My hazelnut test is positive, so it must be simple PFAS.’	No. Cross-reaction sometimes needs to be distinguished from primary allergy.
‘If I tolerate a cooked food, I can always eat it cooked.’	Not always. It depends on the food and proteins involved.
‘PFAS reactions are always mild.’	Most are mild and oral, but more significant reactions are possible.
‘Everyone with PFAS needs adrenaline.’	No. The decision depends on your history and risk level.
‘Pollen immunotherapy will cure my food allergy.’	This benefit has not been demonstrated reliably enough.

What helps your allergist

Before the appointment, if possible record:

the exact food and its form: raw, cooked, juice, smoothie, purée, roasted…;
the approximate amount;
the delay before the first symptoms;
the symptoms: mouth only or beyond the mouth;
the season and whether you have pollen rhinitis;
exercise, NSAIDs, alcohol or another associated circumstance;
similar foods that you eat without a problem.

Décrire ma réaction alimentaire

Allergic rhinitis and rhinoconjunctivitis Adrenaline auto-injector Prepare for allergy tests

Do not multiply avoidance measures

Do not remove several fruit, vegetables or tree nuts that you eat without a problem simply because they appear on a cross-reaction list. Avoidance should be guided by your clinical history and the team’s advice.

Main references

Al-Shaikhly T, Cox A, Nowak-Wegrzyn A, et al. An International Delphi Consensus on the Management of Pollen-Food Allergy Syndrome: A Work Group Report of the AAAAI Adverse Reactions to Foods Committee. J Allergy Clin Immunol Pract. 2024;12(12):3242-3249.e1. doi:10.1016/j.jaip.2024.09.037. PMID: 39488768.
Santos AF, Riggioni C, Agache I, et al. EAACI guidelines on the diagnosis of IgE-mediated food allergy. Allergy. 2023;78(12):3057-3076. doi:10.1111/all.15902. PMID: 37815205.
Santos AF, Riggioni C, Agache I, et al. EAACI guidelines on the management of IgE-mediated food allergy. Allergy. 2025;80(1):14-36. doi:10.1111/all.16345. PMID: 39473345.
Giovannini M, Skypala IJ, Caubet JC, Du Toit G, Nowak-Wegrzyn A. Diagnosis and Management of Pollen Food Allergy Syndrome to Nuts. J Allergy Clin Immunol Pract. 2024;12(3):599-604. doi:10.1016/j.jaip.2024.01.025. PMID: 38280450.

This sheet provides general information. It does not diagnose a condition and does not replace an emergency plan, medical consultation or personalised advice from your healthcare professional.

Scientific review: September 2026 · sosallergo.fr

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