Hives or a swollen mouth after a salad, a curry or a sausage, and no obvious culprit? Mustard is one of the 14 allergens that must be declared on EU food labels, because it hides in so many sauces and spice mixes. Our test checks your blood for IgE to a whole mustard extract and to its main seed protein, Sin a 1, as part of 300 allergens and allergen components.
Mustard seeds come from plants in the cabbage family. The main allergen in yellow mustard is Sin a 1, a 2S albumin. That is a storage protein in the seed, from the same family as major allergens in peanut, tree nuts and sesame. 2S albumins are very stable. They survive heat and digestion, so cooked or processed mustard keeps its allergens.
Sensitisation to Sin a 1 is closely associated with reactions to mustard itself. The whole mustard extract on the panel also captures other mustard proteins, such as lipid transfer proteins and profilin, which are more often shared with pollens and other plant foods.
In studies from Spain, most people with confirmed mustard allergy were also sensitised to mugwort pollen, and many reported reactions to other plant foods such as nuts, fruits and legumes. Shared plant proteins are thought to explain the link.
So a mustard result is most useful next to mugwort and the other plant foods on the panel. One finger prick shows them side by side.
Reactions people describe include itching or swelling of the mouth and lips, hives, stomach pain and vomiting. Some report wheezing, and severe reactions have been described, sometimes after only a small amount hidden in a sauce or spice mix.
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.
Your finger-prick sample goes to the lab, which measures IgE to a whole mustard extract and to one single mustard protein (molecular component). Your lab report gives each a measured value and class, from Negative to Very high. A positive result shows sensitisation, not a clinical allergy. Discuss the result with a doctor before you change what you eat.
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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.
People commonly report itching or swelling of the mouth and lips, hives, stomach pain or vomiting soon after eating mustard. Some report wheezing. Swelling of the throat or trouble breathing is an emergency: call 112 (EU) or your local emergency number.
Mayonnaise, salad dressings, sauces, marinades, curries, pickles, sausages and spice mixes often contain mustard. In the EU it must be declared on the label of packaged food. For loose food, such as in restaurants, you can ask staff for allergen information.
Not reliably. The main mustard allergen, Sin a 1, is a 2S albumin that holds up well to heat and digestion. Cooking does not remove it. If you have reacted to mustard, ask a doctor which foods apply to you.
In some people, yes. Mustard allergy has been linked to mugwort pollen sensitisation, especially in Spain. The test checks mustard and mugwort in the same sample, so you can see whether both show up.
