Hives after a burger, a curry or a salad, and onion is the one thing they share? Onion is in most savoury food, often as powder. Our test checks your blood for IgE antibodies to a whole onion extract, as part of 300 allergens and allergen components including garlic, peach and mugwort pollen.
Onion belongs to the Allium family, with garlic, leek, chives and shallot. IgE-mediated onion allergy is uncommon, but it is real. A lipid transfer protein (LTP) has been described in onion allergy. LTPs survive heat and digestion, so with this pattern cooked onion can matter as well as raw.
Two common onion experiences are not allergy at all. Watering eyes when you chop an onion come from an irritant gas the onion releases. Bloating and wind after onion come from fibres that gut bacteria ferment. Neither involves IgE.
After eating onion, people describe itching in the mouth, hives, swelling or stomach cramps. People who handle onion a lot, such as kitchen staff, sometimes describe itchy hands, a runny nose or wheezing when cutting it.
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.
A positive onion result shows that your blood has IgE that recognises onion proteins. It does not tell you that you will react, or how strongly.
If peach LTP (Pru p 3) also shows up, a doctor may look at an LTP pattern across several plant foods. If garlic and mugwort show up, that points to a spice-and-pollen pattern. Take the result to a doctor before you change what you eat.
Your finger-prick sample goes to the lab, which measures IgE to a whole onion extract. A whole extract contains the mix of proteins in onion, so it shows whether you are sensitised to onion as a whole, not which single protein your antibodies recognise. Your lab report gives a measured value and class, from Negative to Very high, on the same report as garlic, peach and mugwort.
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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.
Bloating and wind after onion are very common and come from fibres your gut ferments. That is not allergy. An allergy involves IgE antibodies, which this test measures. A doctor puts the result together with your symptoms.
Some people report that. It depends on which onion proteins their antibodies recognise. Lipid transfer proteins survive cooking, so with that pattern cooked onion can matter too. Ask a doctor what your result means for you.
No. Chopping onion releases an irritant gas that makes everyone's eyes water. That is not IgE. Itchy, swollen eyes or hives after touching onion are a different story worth raising with a doctor.
