Allergy and intolerance
IgE antilichamen hazelaar
Antibodies against hazel pollen; shows whether the immune system is sensitive to this tree pollen, not whether it bothers you.
Everything about this testWhat it measures
The hazel is a shrub that often grows in gardens, parks and hedgerows. It is one of the first plants to flower each year, usually from January to March and in mild winters sometimes earlier. Hazel pollen is very similar to that of birch and alder, so people who are sensitive to birch often also have antibodies against hazel. This test measures the amount of IgE antibodies against hazel pollen in the blood, in kU/l; it is about pollen in the air, not about eating hazelnuts.
- Sensitization to hazel pollen: the body has made IgE antibodies against hazel pollen
- Support in working out hay fever that starts early in the year, together with the history of the symptoms
High
A value above the cut-off means that you have IgE antibodies against hazel pollen: sensitization. That is not the same as an allergy. In people with symptoms such as sneezing, a blocked or runny nose, itchy or watery eyes or shortness of breath early in the year, often as early as January or February, a positive result fits hay fever from tree pollen. Because hazel pollen is very similar to birch pollen, the result for birch is often positive as well. Some people with this hay fever get itching or a burning feeling in the mouth when eating hazelnut or apple; this is usually a cross-reaction and not a severe food allergy. In people without symptoms, a positive result only means that the antibodies are there; no treatment follows.
Low
A value below the cut-off means that no IgE antibodies against this allergen were found. An IgE-mediated allergy to this allergen is then much less likely, although it is not completely ruled out. Symptoms can also come from another allergen that was not tested, or have a non-allergic cause.
If your result is abnormal
The GP mainly looks at the history: in which months and where the symptoms occur, and whether there are symptoms in the mouth after eating fruit or nuts. With a positive result and matching symptoms, advice follows to reduce contact with pollen, such as keeping windows closed on dry, sunny days, and if needed medication for the nose and eyes. With a lot of symptoms despite medication, an allergist or ENT specialist can discuss immunotherapy, where the result for single allergens helps determine which pollen it targets.
Reliability
A positive IgE result shows sensitization, not allergy: it only says that there are antibodies, not that you get symptoms from them. The Dutch medical specialists' guideline (FMS) on upper airway allergy says this literally and recommends choosing a test for single allergens based on the history of the symptoms; for food allergy, the FMS guideline on food challenge testing calls the history of the symptoms the cornerstone of diagnosis and a food challenge in hospital the gold standard. The result therefore only means something if it fits when, where and after contact with what you get symptoms. A positive result without symptoms is not treated.
Limitations
- Sensitization without symptoms is common; the result can only be interpreted together with the history of the symptoms.
- Related allergens can recognize each other's antibodies (cross-reaction), for example pollen and nuts or fruit; a positive result then does not mean that this particular allergen causes the symptoms.
- The test measures all proteins from the allergen source together; testing for individual proteins (components) can say more in case of doubt.
- Laboratories use different measurement methods and cut-off values; results from different labs cannot be compared one to one.
How common is this
Hay fever is common and often starts at a young age. According to the Longfonds (Dutch lung foundation), trees such as hazel, alder and birch cause symptoms from January to May; hazel and alder flower first. Sensitization is more common than the allergy itself.
Who is this useful for
Useful with symptoms of the nose, eyes or airways that come back every year early in the year, from January to March, especially outdoors on dry, mild days. Because hazel, alder and birch cross-react strongly, the result says the most together with the test for birch pollen and the history of the months in which you have symptoms. For a suspected allergy to eating hazelnuts there is a separate test. In people without such symptoms, the test adds nothing: sensitization without symptoms is not a disease and is not treated.
Downsides and risks
- A positive result can wrongly give the impression that you should avoid hazelnuts; the test is about pollen in the air, not about food.
- A normal result does not rule out symptoms in spring from other trees or other causes.
Sources
- NVKC, allesovertesten.nl: Allergie (RAST)
- FMS Richtlijnendatabase: Allergie van de bovenste luchtwegen, module Aanvullende diagnostiek
- FMS Richtlijnendatabase: Voedselprovocatie, module Plaatsbepaling diagnostiek voedselallergie
- Thuisarts.nl: Ik heb allergie
- Thuisarts.nl: Ik heb hooikoorts
- Longfonds: Hooikoorts
Always discuss an abnormal result with your GP. If a result is strongly abnormal, we try to reach you as soon as possible. Read your result yourself as well and contact your GP if in doubt. A test does not make a diagnosis. Read more about risks and results