A few facts about ambrosia
The perennial-leaved ragweed is a plant of the asteraceae family, native to North America. The species was brought to Europe and to our country accidentally, in the second half of the 19th century. It probably appeared as a result of imported agricultural goods. The plant produces massive quantities of seeds, which cause it to spread easily. Ambrosia can adapt to different environmental conditions, such as temperature, light, and soil. In addition, it negatively affects crops by hindering their growth and development. It restricts their space, as well as their access to water, light and valuable nutrients. It also threatens weeds, which are often a source of food for many animals [1]. On the other hand, it is also considered a medicinal plant. It has a supportive effect in the treatment of fungal and bacterial infections [2].
Ragweed allergy not so rare
Allergic symptoms can occur mainly due to perennial and trillium ragweed. They are less frequently caused by western or coastal ragweed. This plant can be found in sunny locations with dry soil and low fertility. It is regularly observed at grain clearing points, at railway transfer stations and in fields. The pollen grains are lightweight, allowing them to travel long distances [3].
The pollen season for this plant starts in mid-August with low concentrations and lasts until October. High pollen levels in the air are observed at the end of August and last until mid-September [4].
Ragweed pollen is one of the most allergenic in Europe, but not only [7]. More than 12% of people worldwide show sensitivity to ragweed. Sensitisation can be triggered by as few as 5-10 grains of pollen [8]. In addition to high concentrations of this plant in North America, it is also observed in France, Hungary, Ukraine, southern Austria, northern Italy, and the Balkan countries [3]. In Poland, on the other hand, in 2019 the highest concentrations were recorded in Szczecin, Lublin, Piotrków Trybunalski, Olsztyn, Białystok, Wrocław, Warsaw, and Sosnowiec [10].
Allergy to ragweed pollen can cause, among other reactions, such as:
- conjunctivitis,
- rhinitis,
- asthma,
- atopic dermatitis [11].
Ambrosia and its cross-reactions
Ragweed pollen can cross-react with many foods, as well as selected plants. This is because it contains similar proteins in terms of structure to some fruits or vegetables. This means that when we eat, for example, a banana, kiwi or pepper, we can get allergy symptoms. That is due to a cross-reaction. It happens when our body reacts not only to ragweed allergens, but also when it is confronted with another allergen with a similar structure because it confuses it with the proteins contained in this plant [5].
What does ragweed cross with?
- With pollen – ash, mugwort and chamomile,
- fruits – watermelon, banana, peach, kiwi, melon, sugar melon,
- vegetables – courgette, fennel, carrots, cucumber, peppers, celery,
- other plants – coriander, dandelion,
- honeydew honey [5].
Symptoms resulting from cross-reactivity are most often burning and itching of the mouth, slightly less frequently rhinitis, skin lesions or even asthma attacks [6].
Allergy to ragweed – what to do?
If we suspect that we may be allergic to ragweed, we should seek the help of a doctor – a specialist who will take a medical history and order the appropriate tests. What if the test results are positive? Antihistamines prescribed by a specialist can certainly help.
How can we protect ourselves from ragweed pollen?
- First and foremost, avoid eating foods that may cross-react with ragweed if you notice worrying symptoms.
- Remember to close windows before going to bed during the ragweed pollen season, as ragweed pollen is more easily deposited on surfaces at night time.
- Try to avoid contact with imported animal feed, as it may be contaminated with ragweed pollen.
- Let’s also pay attention to the available bird feeds, as they too can be a source of ragweed pollen spread [9].
- If we want to remove ragweed manually, take precautions. Always wear gloves and protective masks.
- At times of highest ragweed pollen concentrations, avoid being on field crops, dry grasslands, roadside verges and watersides [8].
- Keep up to date with the pollen calendar. Then we will know when ragweed pollen concentrations are highest.
Natalia Gajek
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translation: Julia Majsiak
