Fewer dust mites do not necessarily mean fewer asthma attacks.
This is a new health information message to emerge from the September update of "Hot Topics", the consumerised medical research data available on the Medibank Private website.
"Hot Topics" is produced monthly by the Cochrane Consumer Network in association with researchers from its parent organisation, the highly regarded international research body, the Cochrane Collaboration.
The Cochrane Consumer Network provides the general public with access to evidence-based information across a wide range of medical conditions, medicines, drugs, surgery, alternate therapies and lifestyle and dietary changes.
Commenting on the dust mite findings, international convenor for the Cochrane Consumer Network, Hilda Bastian, says that evidence from trials show that while mites can trigger asthma attacks, smaller quantities of dust mites do not mean a reduction in asthma attacks.
"Unfortunately it might only take a few dust mites to cause an asthma attack."
Consequently, she says, people with asthma may not experience a significant drop in asthma attacks from house-cleaning and chemical cleaning.
"If anything, some chemicals might make things worse.
"It is also impossible to eradicate dust mites completely. They are not just in obvious piles of dust but gather where people and animals frequently sit or where they sleep which means that beds, bedding and carpets and upholstered furniture have high levels of house dust mites.
"Mite droppings - which are the allergen rather than the mites themselves - also tend to float in the air."
The latest Cochrane "Hot Topics" also reveal that artificial bedding can actually harbour more dust mites than feather bedding. "Studies have shown that people with asthma who used artificial bedding had more asthma attacks than those using feather bedding," says Ms Bastian.
"The suggestion is that feather pillows may gather fewer dust mites because the covers they are in are more tightly woven, making it hard for dust mites to get in.
"Ultimately, personal trial and error could well be the best guide."
The latest Cochrane Hot Topics data also suggests the use of immunotherapy can result in fewer asthma symptoms and less need for asthma drugs.
Immunotherapy involves immunising people by injecting them with their specific allergen in an attempt to neutralise their body's response.
"However, people getting the injections need to have them where there is access to the best treatment should there be a severe reaction," says Ms Bastian.
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