Ragweed Pollen Allergy

What is Ragweed?

Ragweed is a flowering plant with the scientific genus name ‘Ambrosia’, it is usually found in North America, but it is becoming more common in parts of Europe.  In the USA it is thought to be one of the main causes of pollen related allergies in late Summer to November.  Due to colder temperatures in Europe pollen is usually found September to October.

Should we be worried about Ragweed in Europe?

There are estimates that in the next 20 years the spread and sensitisation to ragweed will more than double in Europe, with the plant predicted to expand into areas where it is currently rare (Germany, France, and Poland). 

Researchers are predicting an increase in the number of Europeans suffering from ragweed pollen allergy. This is thought to be due to the high concentrations of pollen a single plant produces, the size of the pollen particles, which are small enough to carry it long distances and increasing pollution in European cities which holds pollen in the air for longer.

An increase in global temperatures could also result in a longer pollen season for Europe, much more like that of the USA.  Ragweed unfortunately grows at a much quicker rate in warmer climates and has been reported as growing back after its removal.

What are the allergens involved?

Amb a 1 is thought to be the most important ragweed allergen (in older texts it may be referred to as “antigen E”, with 95% of ragweed allergic patients being sensitised to this protein. 

Other allergens found in ragweed are incredibly similar in structure which makes sufferers of ragweed pollen allergy excellent candidates for immunotherapy, which helps to reduce the allergic symptoms of ragweed induced rhinitis. 

Linked Allergies

Ragweed Allergy is thought to be linked to Pollen Food Allergy Syndrome.  Those who have already been sensitised to the pollen of this plant may later have oral allergy type symptoms to bananas, watermelon, courgette (zucchini), cucumbers and squash.

What are the symptoms?

Ragweed allergy is associated with all the usual hayfever symptoms (also called allergic rhinitis)

  • itchy eyes,
  • scratchy throat,
  • runny nose,
  • headaches,
  • sneezing,
  • nasal congestion.  

For those who have pollen as an asthma trigger it can cause wheezing, coughing and other asthma symptoms.

What is the treatment?

Usual hayfever medications, such as antihistamines, nasal drops and eye drops can be used to improve the symptoms of ragweed allergy.  For those who also suffer wheezing and asthma like symptoms be sure to continue using your preventer inhalers and speak to your GP / asthma nurse to discuss if the symptoms are getting worse.

In the USA there are more immunotherapy options for prevention of symptoms for allergic rhinitis, including new ones for Ragweed, but this is generally not an option on the NHS in the UK.

If you think you suffer from any of these allergies you should seek medical advice from your GP, allergist, or dietician










Research Papers

Biological weed control to relieve millions from Ambrosia allergies in Europe, 2020

Ragweed story: from the plant to the patient, 2020

Cross‐reactivity in allergy: A double‐edged sword, 2019

Ragweed Pollen Allergy: Burden, Characteristics, and Management of an Imported Allergen Source in Europe, 2018

Modifiable Risk Factors for Common Ragweed (Ambrosia artemisiifolia) Allergy and Disease in Children: A Case-Control Study, 2018

Climate Change and Future Pollen Allergy in Europe, 2017(NB. this paper was discussed in the top paper – “Biological weed control to relieve millions from Ambrosia allergies in Europe” the more up to date paper predicts a much lower sensitisation rate due to improved data collecting techniques.)

Your Grandchildren’s Pollen? Modelling the Future of Ragweed Sensitization in Europe, 2017

In children allergic to ragweed pollen, nasal inflammation is not influenced by monosensitization or polysensitization, 2016

Ragweed-induced allergic rhinoconjunctivitis: current and emerging treatment options, 2015

Ambrosia artemisiifolia (ragweed) in Germany – current presence, allergological relevance and containment procedures, 2015

Published by Jemma D

I love to write about food allergies, asthma and eczema.

2 thoughts on “Ragweed Pollen Allergy

  1. There are 17 species of ragweed in the United States. The weeds grow in most regions, typically blooming and producing a fine-powder pollen from August into November. An allergist can set you on the right track to handle ragweed allergies for the long term.


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