Birch

severe allergen

Betula

tree pollen

Birch pollen is one of the most allergenic tree pollens worldwide. It contains the protein Bet v 1, which is the primary allergen responsible for birch pollen allergy and is also the protein behind many food cross-reactions. A single birch catkin releases about 5.5 million pollen grains, and a mature tree can have thousands of catkins.

Grain Size

22-28 micrometres

Prevalence

Very common in the northern United States, Canada, and throughout Europe. Birch is the most significant allergenic tree in northern temperate climates.

Allergy Severity

severe

Bloom Period

Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

Sep

Oct

Nov

Dec

Bloom Peak

Cross-Reactivity

If you're allergic to birch pollen, you may also react to:

Apples, pears, cherries, peaches (Rosaceae family fruits)
Hazelnuts, almonds, walnuts
Carrots, celery, parsley
Soy (significant cross-reactor via Gly m 4 protein)
Alder, hazel, hornbeam (related tree species)

Practical Tips

Birch-fruit syndrome: if you're allergic to birch, you may react to raw apples, cherries, and peaches. Cooking these foods breaks down the cross-reactive proteins.
Birch season is short but intense — typically 2-4 weeks in April.
Consider immunotherapy (allergy shots) — birch pollen immunotherapy is one of the best-studied and most effective.
HEPA air purifiers are especially effective against birch pollen particles.