Itchy throat after pecan pie, or hives after a breakfast bar you thought was safe? Pecan is walnut's closest relative on the nut shelf, and the two are hard to tell apart for your immune system too. Our test checks your blood for IgE antibodies to whole pecan and three single pecan proteins, as part of 300 allergens and allergen components, next to walnut, so you can see both at once.
Pecan comes from a North American hickory tree in the walnut family. The proteins that matter for allergy are storage proteins: Car i 1 (a 2S albumin), Car i 2 (a vicilin) and Car i 4 (a legumin). They are stable to heat and digestion, so roasted, baked and candied pecans still carry them.
These proteins are very close to walnut's Jug r 1, Jug r 2 and Jug r 4. That is the core of the pecan story: for most people, pecan and walnut results move together.
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 pecan. 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.
In a large European study that challenged children with every common nut, walnut and pecan allergy were strongly linked, and both clustered with hazelnut and macadamia. People with walnut allergy reacting to pecan as well is the rule rather than the exception.
Still, a positive result shows sensitisation, not that you will react. If you have never reacted to pecan, do not cut it out on a result alone. If you have, take the result to a doctor or allergist, who can compare your pecan and walnut values side by side.
The lab measures IgE to a whole pecan extract and to three single pecan proteins (molecular components). Your lab report gives each a measured value and class, from Negative to Very high, next to the five walnut proteins on 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 not, but check rather than guess. Walnut and pecan proteins are so alike that most people who react to one react to the other. Your report shows both side by side; a doctor or allergist can tell you what that means for you.
Yes. Pecan is a tree nut from the walnut family, and EU food labels must declare it as an allergen.
One measures the whole nut, the other three measure single storage proteins: Car i 1, Car i 2 and Car i 4. Seeing which proteins your antibodies recognise gives a doctor more to work with than one number for the whole nut.
