Spring hay fever that you have always put down to birch? Ash flowers at almost the same time, and its pollen is a common, often overlooked trigger in Ireland, the Netherlands and Germany. Our test checks IgE to Fra e 1, the main ash pollen protein, as part of 300 allergens and allergen components, right next to birch, so the two are no longer mixed up.
Ash (Fraxinus excelsior) is a large, wind-pollinated tree. It flowers before its leaves open, in purple-black clusters that are easy to miss, and releases plenty of pollen into the air.
Ash belongs to the olive family (Oleaceae). Its main allergen, Fra e 1, is an Ole e 1-like protein, closely related to Ole e 1 from olive pollen. It is not related to birch, even though the two flower together.
Symptoms are the usual spring hay fever set: sneezing, a runny or blocked nose and itchy, watery eyes, sometimes a cough on high-pollen days.
Because ash and birch pollen fill the air in the same weeks, people often assume birch is the cause. Studies from central Europe describe ash pollen allergy as common and easy to overlook for exactly that reason.
Ash and olive are cousins. Fra e 1 and Ole e 1 are so similar that IgE to one usually recognises the other. Olive barely grows in northern Europe, but people sensitised to ash at home can react on a May holiday in Spain, Italy or Greece.
Birch is a different story. Its main protein, Bet v 1, belongs to another family altogether. Seeing ash and birch as separate results tells you whether your blood reacts to one, the other or both, which a single 'tree pollen' guess cannot.
Ash dieback is thinning ash trees across Europe, but many remain in hedgerows and woodland, and pollen still travels far on the wind.
From a finger-prick sample, the lab measures IgE to Fra e 1, the main ash pollen protein (a molecular component), as part of 300 allergens and allergen components. There is no whole ash pollen extract on the panel. Olive (Ole e 1), birch, alder and oak are on the same report, so you see the tree season side by side.
A positive result means your blood shows IgE to ash pollen. That is sensitisation, not a diagnosis. Your lab report gives the value a class from Negative to Very high, to discuss with a doctor.
Page last updated
One finger-prick sample checks IgE to 300 allergens and allergen components, from birch and peanut to cat and house dust mite. Post it to the lab, and about 5 days after it arrives you get a value for every one. Our plain-English guide shows you how to read them. €399 in total, €1.33 per allergen.
In central Europe, Ireland and the UK ash usually flowers from March to April, before its leaves appear. That overlaps with the start of the birch season, which is why the two are easily confused.
You cannot tell from symptoms alone, because both flower in the same weeks and cause the same hay fever. Their proteins are unrelated, so a test that measures both separately shows whether your blood has IgE to ash, birch or both.
Ash is not known for the fruit and nut links that birch has. Its main protein belongs to the Ole e 1-like family, which is not a common trigger for mouth itching after raw fruit. If you notice that, it more likely points to birch, and a test shows both.
Most likely because of ash. Ash's Fra e 1 and olive's Ole e 1 are very similar, so IgE made against ash pollen at home often recognises olive pollen too. That is cross-reactivity, which a doctor can help you read.
