Alder pollen allergy
Hay fever in February, when nothing seems to be flowering yet? Alder catkins release pollen in late winter, often weeks before birch. Our test checks IgE sensitisation to two alder pollen proteins, as part of 300 allergens and allergen components, next to birch and hazelnut.
- Group
- Pollen
- Season
- Roughly February to March in central Europe; from January in mild winters
- Also known as
- alder allergy, Alnus glutinosa, black alder, Aln g 1, early tree pollen
Where you meet it
- Riverbanks, lakesides, wetlands and damp woodland
- Parks, streets and windbreaks planted with alder
- Outdoors on mild, dry days in late winter
What alder pollen is
Alder (Alnus glutinosa and related species) is a tree of riverbanks and damp ground. Its catkins open in late winter, at about the same time as hazel and a few weeks before birch, which is why alder is often among the first pollens of the year.
Alder belongs to the birch family. Its main pollen allergen, Aln g 1, belongs to the same PR-10 protein family as birch's Bet v 1.
What people commonly report
Symptoms are the usual hay fever set: sneezing, runny or blocked nose and itchy eyes. Because they arrive in late winter, they are often mistaken for a cold.
A useful clue: a cold usually brings a sore throat and tiredness and passes in about a week. Pollen symptoms come with itching and tend to track sunny, windy days.
- Sneezing on mild, dry days from February
- Itchy, watery eyes
- A 'cold' that keeps coming back in late winter
Alder, birch and hazel
Most people sensitised to alder pollen are also sensitised to birch, because Aln g 1 and Bet v 1 are so similar. For many, alder is the opening act of a season that runs through birch in April.
Hazel pollen belongs to the same group, flowers at the same time and contains a similar protein. The panel has no separate hazel pollen marker. Raised alder or birch results can reflect this shared protein family, which is cross-reactivity, not a hazel pollen result.
Like birch, alder sensitisation can come with itching in the mouth after raw hazelnut, apple and other foods with PR-10 proteins. That pollen-related pattern is different from sensitisation to hazelnut storage proteins. A doctor can interpret which applies to you.
How the test checks alder
Your finger-prick sample is tested for IgE to two single alder pollen proteins (molecular components) as part of 300 allergens and allergen components. Birch and hazelnut appear on the same report, so you see the family side by side.
A positive result means sensitisation, not a diagnosis. Each value gets a class from Negative to Very high, to discuss with a doctor.
- Aln g 1: the main alder pollen protein (PR-10 family, similar to birch's Bet v 1)
- Aln g 4: a calcium-binding protein (polcalcin) found in many pollens, so IgE to it can make several pollen results rise together
Known cross-reactions
- Birch pollen
- Closely related trees with very similar pollen proteins (Aln g 1 and Bet v 1). Sensitisation to both is common.
- Hazel pollen
- Another birch-family tree that flowers at the same time as alder, with a similar PR-10 protein. Not measured separately on this panel.
- Hazelnut
- Raw hazelnut can cause mouth itching in people sensitised to alder or birch pollen. This is distinct from sensitisation to hazelnut storage proteins.
Sources
- Birch pollen allergy in Europe. Allergy, 2019.
- Pollen Allergens for Molecular Diagnosis. Current Allergy and Asthma Reports, 2016.
- EAACI Molecular Allergology User's Guide 2.0. Pediatric Allergy and Immunology (EAACI), 2023.
Page last updated
300 allergens. One test.
A finger-prick sample at home, sent by post. A detailed lab report typically 5 days after the lab receives your sample, and our plain-English guide to reading it. €300, €1 per allergen.
Questions
When does alder pollen start?
In central Europe alder usually flowers from February to March, and from January after a mild winter. That makes it one of the first pollens many people react to each year, together with hazel.
Is it a cold or tree pollen?
Colds often come with a sore throat, aches and tiredness and clear up within about a week. Pollen symptoms are itchier, follow the weather and keep returning. If you are unsure, a doctor can help, and a test shows whether you are sensitised to alder and birch.
Does the test check hazel pollen?
Not separately. The panel measures alder and birch pollen proteins, which closely resemble the main hazel pollen protein, so people sensitised to hazel pollen often show IgE to them too. If a dedicated hazel pollen result matters for you, a doctor can arrange one.
If I am sensitised to alder pollen, can I eat hazelnuts?
That depends on which proteins you react to and what happens when you eat them. Some people only get a brief itch from raw nuts; others have a separate, more serious nut allergy. Discuss your results with a doctor before changing what you eat.