House dust mite - facts and features - Strefa Alergii
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House dust mite – facts and features

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They are small but annoying. It doesn't also help that dust mites accompany us almost everywhere. Get to know the facts and interesting information about these arachnids.

What are the types of mites?

Mites belong to the arachnid cluster and are a group with about 30 000 species. They are grouped into numerous families. In practice, however, from the perspective of the patient and the clinician, they are divided into house dust mites, storage mites, and others.

Where can we find house dust mites?

They can be found practically everywhere, in soil, water, on plants or in house dust. From an allergologist’s standpoint, the most important are those present in house dust. These include: Dermatophagoides pteronyssinus, Dermatophagoides farinae and Euroglyphus maynei, and those that can be found in flour. These include Acarus siro, Lepidoglyphus destructor, Tyrophagus putrescentiae, and Blomia tropicalis. Most house dust mites are found in mattresses, pillows, blankets, or duvets.  Exposure to storage mites is mainly associated with the workplace of food industry workers, e.g. bakers.

Is it possible to escape from mites?

Dust mites are found all over the world, although there are fewer in some regions and more in others. Most house dust mites are found in warm and humid climates. House dust mites multiply very poorly in dry and cold climates, so localities above 1,500 meters above sea level are considered free of these organisms. The situation is similar in the polar regions. However, improved living conditions with air-conditioned living quarters may affect their development even in these regions.

House dust mite allergy – what symptoms does it cause?

House dust mite allergy is most often manifested by symptoms of rhinitis: sneezing, itching, excessive production of secretions and nasal blockages. Conjunctivitis symptoms, such as burning eyes or tearing, are less common than in other inhalant allergies.  Sensitisation to these arachnids is the strongest risk factor for the development of asthma. Therefore, patients may develop symptoms such as breathlessness, coughing and wheezing. Sensitisation to house dust mites is also common in people with atopic dermatitis. In these people, exposure can aggravate pruritus and impede the healing of skin lesions, or even be the cause.

How to help an allergic person? (Is it possible to get rid of dust mites from our environment)

Numerous methods can lead to a reduction in exposure to house dust mites. We can divide these into physical and chemical methods.

  • In this first group, there are methods based on creating barriers between the human body and the sources of dust mites. They also involve reducing the reproduction of dust mites by creating unfavourable environmental conditions or removing airborne allergens. Barrier methods mainly involve using hypoallergenic bedding that does not allow particles containing dust mite allergens to pass through.
  • Methods for reducing dust mite populations in homes involve lowering the air humidity to below 55% (ideally below 45%), removing potential dust mite breeding sites such as unnecessary carpets, rugs, or curtains, washing at temperatures above 60°C, or freezing pillows, duvets, mattresses, or plush toys.
  • Removing allergens from our environment involves frequent vacuuming using vacuum cleaners equipped with special filters and/or using HEPA filters. Changing the climate from humid and warm to cold and dry, such as going to the mountains, also reduces exposure to dust mite allergens.
  • The use of chemical agents with acaricidal properties can help reduce the number of dust mites in places that are difficult to treat with physical methods, such as sofas, couches, and carpeting. It is usually recommended to use a combination of several methods. However, complete elimination of dust mites from our environment appears to be unlikely.

In patients allergic to house dust mites, allergen immunotherapy has had good results.

Do mites cause cross-reactions?

House dust mites also contain proteins that are not species- or genus-specific.  Patients allergic to house dust mites, whose body produces IgE antibodies to such proteins, show clinical symptoms after exposure to other, often phylogenetically distant organisms.  In addition, clinical symptoms may involve other organs. An example is sensitisation to tropomyosin, a protein that is present in mites, but also in other living organisms. Tropomyosin of mites and shrimps or lobsters is particularly similar.  This is why people who are allergic to house dust mites, which produce IgE against tropomyosin, develop anaphylactic reactions after eating seafood such as shrimps. Allergic reactions may also occur after eating meat containing nematodes or after exposure to cockroach proteins.

It is worth noting that also sensitisation to house dust mite proteins can cause cross-reactions after exposure to storage mites. The reverse reaction is also possible, where a person who acquires sensitisation to one of the storage mites may show sensitisation reactions to the house dust mite.

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translation: Julia Majsiak