Birch pollen allergy
Betula
Birch is a major spring tree pollen. Many people allergic to it also get an itchy mouth from some raw fruits, vegetables and nuts.
What it is
Birch pollen comes from trees and shrubs in the genus Betula, which grow in the cooler parts of the Northern Hemisphere.4 Fourteen species are native to the United States, among them paper, yellow, sweet, gray, river and water birch.4 Birches grow in every state except Hawaii.1
A birch carries its flowers in catkins, with male and female catkins on the same tree. The male catkins form in late summer or fall, stay bare through the winter, then lengthen and open in spring. The female catkins appear with the leaves.4 Wind-carried pollen is the only kind of tree pollen that most people with tree allergies react to.1 Birch is one of the big spring allergy triggers.3
Birch pollen’s main allergen, Bet v 1, belongs to a group of related proteins (PR-10) also found in oak pollen, and a 2015 review reports that these allergens cross-react across birch, oak and their relatives.5
Symptoms it causes
Birch pollen can trigger hay fever, also called allergic rhinitis, when it gets into the body.7 Typical symptoms are a runny or stuffy nose, postnasal drip, sneezing, an itchy nose, eyes, ears and mouth, and red, watery or swollen eyes. Some people also cough, wheeze or feel short of breath.1 In people with asthma, tree pollen can trigger asthma symptoms.1
Birch pollen can also cause symptoms through food. Some proteins in tree pollen resemble proteins in certain fruits, vegetables and nuts, and the immune system can mistake one for the other.1 The result is oral allergy syndrome, also called pollen food syndrome. Up to 50 to 75% of adults allergic to birch pollen get an itchy mouth or throat after eating apple or celery.2 The most common signs are itching or swelling of the mouth, face, lips, tongue and throat, usually right after eating the raw food.2
Rarely, the throat swells enough to make swallowing or breathing difficult. A reaction that affects the whole body (anaphylaxis) is possible but very uncommon.2
Where and when it grows
Birches flower in spring. Most native species flower in April and May, and paper birch can flower into June.4 Across the US, trees as a group release the most pollen from February through April, and in the South they can begin in December or January.1 In Illinois, for example, allergenic trees are usually a problem from March through May.6
Ranges differ by species. Paper birch reaches south to Washington, North Dakota, northeastern Iowa and New England. River birch grows from Connecticut to eastern Iowa and southeastern Kansas, and south to eastern Texas and northern Florida. Water birch grows in the West, east to the Dakotas, Nebraska, Colorado and New Mexico.4
Cross-reactions
The foods linked to birch pollen include apple, apricot, cherry, kiwi, peach, pear and plum; carrot, celery, coriander, fennel, parsley, anise and caraway; and almond, hazelnut, peanut and soybean.1 Some people react to only one food and others to many, and some react only to certain varieties, such as particular apples.2
High heat breaks down the proteins behind oral allergy syndrome, so baked, microwaved or canned forms of a food may cause less of a reaction than raw ones.2 Symptoms tend to get worse during pollen season, but they can happen at any time of year.2
Cross-reactions
| Can also react to | What happens |
|---|---|
| Raw apple, apricot, cherry, kiwi, peach, pear and plum | Proteins in these fruits resemble birch pollen proteins, so eating them raw can make the mouth itch or swell in people allergic to birch pollen.1 |
| Raw carrot, celery, parsley, fennel, coriander, anise and caraway | These vegetables and herbs are on the same cross-reaction list and can cause the same mouth symptoms.1 |
| Hazelnut, almond and peanut | These can cause mouth itching in people with birch pollen allergy. AAAAI advises seeing an allergist if nuts cause mouth symptoms, because mild symptoms may signal a more serious nut allergy.2 |
| Oak pollen | Oak and birch pollen both contain allergens of the same group (PR-10). A 2015 review reports that these related allergens, found across oak, birch and their relatives, cross-react.5 |
Symptoms it can cause
- Can allergies cause sneezing?
- Can allergies cause a runny nose?
- Can allergies cause a stuffy nose?
- Can allergies make your nose itch?
- Can allergies cause postnasal drip?
- Can allergies cause sinus pressure?
- Can allergies cause itchy eyes?
- Can allergies cause watery eyes?
- Can allergies cause red eyes?
- Can allergies cause swollen eyelids?
- Can allergies cause an itchy throat?
- Can allergies cause a sore throat?
- Can allergies make your mouth itch?
- Can allergies cause a cough?
- Can allergies cause wheezing?
- Can allergies cause shortness of breath?
- Can allergies cause chest tightness?
- Can allergies cause swollen lips or a swollen face?
- Can allergies cause headaches?
- Can allergies make your ears feel full?
- Can allergies make you tired?
Related conditions
Guides
When to get help
See an allergist if
- Allergy symptoms last for several months of the year
- Allergies bring repeated sinus problems, a blocked nose or trouble breathing
- Over-the-counter remedies don’t control your symptoms
- Allergies or asthma get in the way of daily life
- You often wheeze, cough at night or after exercise, or feel short of breath
Based on ACAAI’s “When To See an Allergist”. General information, not medical advice.
Questions
Why does my mouth itch when I eat a raw apple?
In people allergic to birch pollen, this can be oral allergy syndrome. Proteins in some fruits are very similar to proteins in pollen. Up to 50 to 75% of adults allergic to birch pollen get an itchy mouth or throat from apple or celery.2
When is birch pollen season?
Spring. Most native birches flower in April and May, and paper birch can flower into June. The male catkins form the summer or fall before and open as they lengthen in spring.4
Does oral allergy syndrome happen only in spring?
No. It can happen at any time of year, but it tends to get worse during the pollen season of the plant involved.2
Does a birch allergy mean I am allergic to nuts?
Not necessarily, but peanut, almond and hazelnut can cause mouth itching in people with birch pollen allergy. AAAAI advises seeing an allergist if nuts make your mouth itch, because mild mouth symptoms may signal a more serious nut allergy.2
Sources
- Tree Pollen Allergy. Asthma and Allergy Foundation of America. Read on October 15, 2026.
- Oral Allergy Syndrome (OAS) or Pollen Food Syndrome. American Academy of Allergy, Asthma and Immunology. Read on October 15, 2026.
- Spring Allergies. American Academy of Allergy, Asthma and Immunology. Read on October 15, 2026.
- Betulaceae—Birch family: Betula L., birch. USDA Forest Service, Woody Plant Seed Manual. Read on October 15, 2026.
- Tree pollen allergens—an update from a molecular perspective. Allergy (Asam C, Hofer H, Wolf M, Aglas L, Wallner M), 2015. Read on October 15, 2026.
- Allergenic Plants. University of Illinois Extension. Read on October 15, 2026.
- Allergens and Pollen. Centers for Disease Control and Prevention. Read on October 15, 2026.