Itchy throat after a slice of carrot cake, or hives after a salad with walnuts on top? Walnut is one of the tree nuts that people in Europe react to most often. Our test checks your blood for IgE antibodies to five single walnut proteins, as part of 300 allergens and allergen components, so you can see whether you are sensitised to walnut and to which proteins.
The walnut proteins that matter for allergy fall into two groups. Storage proteins are what the seed keeps as food for the young plant: Jug r 1 (a 2S albumin), Jug r 2 and Jug r 6 (vicilins) and Jug r 4 (a legumin). They resist heat and digestion. Jug r 1 in particular is linked to walnut allergy with reactions beyond the mouth.
Jug r 3 is a lipid transfer protein (LTP). It is also stable to heat, and it looks like LTPs in peach, apple and other plant foods. In southern Europe, walnut sensitisation is often part of a wider LTP pattern that starts with peach.
People describe itching or tingling in the mouth and throat, swollen lips, hives, stomach cramps or vomiting, usually within minutes to two hours of eating walnut. Some report wheezing or feeling faint.
Swelling of the lips, tongue or throat, trouble breathing or feeling faint after eating is an emergency. Call 112 (EU) or your local emergency number. Do not wait for a test.
Walnut and pecan come from the same plant family, and their storage proteins are very alike. Studies of people with walnut allergy find that reacting to pecan as well is the rule rather than the exception. Hazelnut and walnut also share similar vicilins, so IgE to both is common.
Plenty of people show IgE to walnut and eat it without a problem. A positive result shows sensitisation, not that you will react. If you have never reacted to walnut, do not cut it out on a result alone. If you have, take the result to a doctor or allergist.
The lab measures IgE to five single walnut proteins (molecular components). There is no whole walnut extract on the panel. Your lab report gives each a measured value and class, from Negative to Very high, next to pecan, hazelnut, peach and the rest of the panel. Treat it as a pattern to discuss with your doctor, not a diet plan.
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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.
Often, yes. Walnut and pecan are close relatives with very similar storage proteins, and studies find most people with walnut allergy also react to pecan. Your report shows walnut components and pecan separately, so a doctor can look at both.
No. Tree nut is a label for many different nuts. Some pairs are closely linked, like walnut and pecan or cashew and pistachio, others much less so. The test shows each nut on its own, so you can see which ones your antibodies recognise.
Cold-pressed walnut oil can contain walnut protein. If you have reacted to walnut before, ask your doctor or allergist what applies to you before using it.
It shows IgE to a walnut storage protein that survives heat and digestion. Specialists look at it closely because it is linked to reactions beyond the mouth. It is still sensitisation, not a diagnosis. A doctor reads it together with your history.
