Biology and damage

Sengemider is also known as house dust mites, and there have probably been house dust myths as long as there have been people. They are otherwise quite difficult to spot. The eight-legged animals are white and no larger than just 0.1 to approx. half a millimeter, so they are not so easy to see with the naked eye, and they are even sometimes difficult to see under the microscope. Here at home you usually find the European house dust mite (Dermatophagoides pteronyssinus) or the American house dust mite (Dermatophagoides farinae) .

Since the mites of the genus Dermatophagoides all live on rejected hair and scales from humans and animals, there will be really good living conditions for myths, especially in the environs, unless one is very thorough with the replacement and cleaning of bedding. Studies have shown that between one and a half grams of skin scales per day are given per day. human being. Although it doesn’t sound like much, it’s still enough to give thousands of myths in a whole year!

Depending on how hot or cold there is and what is humidity there is, it will affect the reproduction rate, but since every one she is able to lay between 40 and 80 eggs in the 3 to 5 months she lives, it could easily become a lot or myths in a season. After the eggs are laid, they will usually be between 1 and 2 weeks before, and the myths will be several stages before they become adults, as is the case with many other insects. After hatching, this development takes place about approx. 4 to 8 weeks.


Like so many other animals, hair sides or house dust mites are a kind of nature’s garbage man, living on dead skin scales from humans and animals, and thereby helping to break down organic waste. Such skin screams are constantly dripping from us, and it also seems quite peaceful that small mites can clean up after us, but since many people suffer from house dust mite allergy, the incidence of house dust mites or their mites is clearly undesirable in our homes.

More than 200,000 Danes suffer from allergies as a result of house dust mites, but it is rightly the remnants of the meadows that give the problem. It is not only the mites in themselves that can cause allergic reactions in some people, but especially the small particles or allergens from the Mid-sheath’s skin and excrement, which are easily swirled up in the air when sweeping a smooth floor, or nests it beds. In this way, these small particles are inhaled easily and come deep into the lungs, which can cause allergies in some.

Husstøvmide kaldes også sengemide
Husstøvmide eller sengemide (Latin: Genus Dermatophagoides)


People who suffer from asthma often live with the symptoms of an allergy that has arisen as a result of inhalation of particles from house dust mites and hairpins. The problem is such that one should be examined by a doctor. The Asthma and Allergy Association also has a website that contains good information about the subject.

Prevention and control

It is not the occurrence of dust in itself that can lead to the occurrence of house dust mites or hair slides, but the presence of suitable food in the form of dead skin scales. Hygiene is therefore a topical issue in both prevention and control of the mites.

Bed mites or house dust mites are best in relatively high humidity. Very best if they are between 17 and 32 o C and a relative humidity of between 55 and 75%. Therefore, a regular dehumidification and venting of the affected premises can both prevent and remedy the problem. This is due to the fact that the skin sides and house dust mites absorb moisture through the skin so that they will dry out and die if the humidity is sufficiently low. In winter, when the relative humidity is low, there are particularly good opportunities to keep the stock of mites down.

Thorough and frequent cleaning will also partly remove the food items in the form of the dead skin scales, and partly remove the mites’ own excrement and hides and the individual mites that may be there. Venting is therefore one of the best precautions to prevent allergy. Asthma patients and house dust mite allergy sufferers can also obtain a special mattress cover which is so finely meshed in the weaving that any mites are encapsulated in the mattress, so as to avoid taking them by inhalation and the like.

Especially after our homes have been so insulated as is the case, problems with high humidity have arisen. Carefulness in connection with flower watering, cooking, laundry, etc. can also make the home’s indoor climate less humid. It will therefore also make sense to keep the door closed to the bathroom after a shower, rather than spreading the moisture throughout the home.

Also avoid passive smoking which can make children more allergic to both house dust mites, pollen and fur animals.

Copyright 2021 Absolut Skadedyrsservice A / S

Flere inden for samme art


Læs mere om husmider hos Forlaget Pestium

Læs mere om insekter i hjemmet hos Miljøstyrelsen

Læs mere om biolog, Henri Mourier