Hay fever on a late-summer trip to inland Spain, the Middle East or the American Southwest? Russian thistle, the plant behind the rolling tumbleweed, is one of the main weed pollens in dry, salty landscapes. Our test checks IgE to Russian thistle and two of its proteins, including the marker Sal k 1, as part of 300 allergens and allergen components.
Russian thistle (Salsola kali, also sold as prickly saltwort) is not a true thistle. It is a spiny, bushy member of the amaranth family (Amaranthaceae) that tolerates salt and drought. When it dies, the dry plant snaps off and rolls in the wind as a tumbleweed.
In dry inland areas of Spain and across the Middle East it is one of the most important pollen sources in late summer. In Finland, Ireland, the Netherlands and Germany it is only a small coastal plant and rarely matters at home. It matters mainly for travellers and for people who have lived in dry regions.
People sensitised to Russian thistle report the usual hay fever set: sneezing, a runny or blocked nose and itchy eyes, and in some cases a cough or wheezing on high-pollen days.
In regions where it grows, it flowers after the grasses and olive have finished, so symptoms that start or return in July and August point in its direction.
Sal k 1 is a pectin methylesterase and the main Russian thistle allergen. IgE to it is used as a marker for genuine sensitisation to the amaranth family of weeds, rather than to a protein shared by many plants.
Sal k 5 is an Ole e 1-like protein, the same family as goosefoot's Che a 1, and the two can cross-react. Goosefoot and amaranth pollen also cross-react with Russian thistle, so seeing all three on one report helps a doctor read the pattern.
From a finger-prick sample, the lab measures IgE to the three Russian thistle markers below as part of 300 allergens and allergen components. Goosefoot (whole extract and Che a 1), amaranth, olive, Bermuda grass and wall pellitory are on the same report, which covers most of the pollens you meet on a Mediterranean summer trip.
A positive result means your blood shows IgE to Russian thistle pollen. That is sensitisation, not a diagnosis. Each value gets a class from Negative to Very high, to discuss with a doctor.
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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.
No. Despite the name and the spines, Russian thistle (Salsola) belongs to the amaranth family, with goosefoot, beet and spinach. The dried plant is the tumbleweed you see in westerns.
In Spain and other dry regions it flowers from about July to September, sometimes into October. That is after grass and olive season, so it explains late-summer hay fever in those areas.
Only in small numbers, mostly on sandy coasts. It is rarely a pollen problem in Finland, Ireland, the Netherlands or Germany. It matters if you travel to or have lived in dry regions such as inland Spain, the Middle East or the western US.
