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Oak pollen

Oak (Quercus robur) is airborne here from may to june, peaking the second half of May. Allergenic potency: moderate. Cross-reacts with apple, cherry, hazelnut, carrot and others.

This is reference information, not a diagnosis and not a treatment plan. A pollen calendar cannot tell you what you are allergic to, and no page can clear a food as safe for you — only the label on the packet in your hand and the clinician who knows your history can do that. Anything beyond mild, short-lived symptoms in the mouth or nose — swelling that affects breathing or swallowing, hives away from the mouth, wheeze, vomiting or faintness — is an emergency question, not a reading question.

● peak weeks · ○ usually airborne. Typical mainland window from the national aerobiology monitoring programmes of the region · checked 2026-09-06

Where it grows here

Pedunculate oak reaches its northern limit in this region — common in Estonia, Latvia, Lithuania, Denmark and southern Sweden, scattered and coastal in southern Finland, absent further north. It is a heavy pollen producer and a long-lived one, so a single park oak keeps flowering for a human lifetime.

When it is in the air

Oak flowers as the birch season ends, through the second half of May and into June. For someone sensitised to the whole birch group, that extension is the reason spring symptoms do not stop when the birch catkins fall: the same family of protein is still in the air for another two or three weeks.

What it feels like

The familiar spring set — itchy eyes, blocked nose, sneezing — arriving late enough in May that people start to suspect grass instead. The distinction matters, because grass allergy is managed and treated as a separate thing.

What it cross-reacts with

Que a 1 is another Bet v 1 homologue, so oak belongs to the birch group and carries the same food cross-reactions. Isolated oak allergy without birch sensitisation is unusual. The practical effect of oak is to lengthen the season rather than to add a new one.

Related pollens: birch, alder, hazel, hornbeam and beech.

Foods reported to cross-react:

AppleCherryHazelnutCarrot

A cross-reaction is not the same as a food allergy that started with food, and the difference decides how serious it is. Read how oral allergy syndrome works before drawing conclusions from this list, and note that several of these foods also appear on the fourteen declarable EU allergens for entirely separate reasons.

Named allergen molecules: Que a 1 (PR-10, a Bet v 1 homologue). These are the official WHO/IUIS names, and they are what a component-resolved blood test reports.

What actually helps

The end of May is the handover fortnight between the tree and grass seasons. Keeping a simple diary through it, marking days as bad or fine, is more useful than any single test: two clearly separated bad periods point at trees and grasses separately, one continuous run points at the overlap.

What gets misread

Oak is confused with the grass season it runs into, and oak pollen is also confused with the far more visible conifer pollen of the same weeks. The yellow film on cars in late May is pine and spruce, not oak.

Sources: Regulation (EU) No 1169/2011, Annex II · Commission Implementing Regulation (EU) No 828/2014 (gluten claims) · WHO/IUIS Allergen Nomenclature · season windows from the national aerobiology monitoring programmes of Estonia, Finland, Sweden, Denmark and Norway · cross-reaction patterns paraphrased from the allergy literature and EAACI material · checked 2026-09-06

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