Itch mite - lodgers in the skin
Luise Heine has been an editor at since 2012. The qualified biologist studied in Regensburg and Brisbane (Australia) and gained experience as a journalist in television, in the Ratgeber-Verlag and in a print magazine. In addition to her work at , she also writes for children, for example for the Stuttgarter Kinderzeitung, and has her own breakfast blog, “Kuchen zum Frühstück”.
More posts by Luise Heine All content is checked by medical journalists.Small arachnids that bore caves and passages under human skin - such little monsters really do exist. They are called Sarcoptes scabiei and they cause a disease called scabies. Find out where the mites are preferred and what you can do about them.
How do I recognize an itch mite?
The causative agent of scabies in humans is the type of mite Sarcoptes scabiei, which lives in the skin. The mite is very small, rather rounded and has stubby legs. The adult females are 0.2 to 0.5 millimeters tall and can sometimes be seen as tiny black dots with the naked eye.
The passages that the animals dig into the skin can be clearly seen with a magnifying glass. They appear dark or light reddish and are up to 2.5 centimeters long. However, it usually takes a few weeks before patients complain of symptoms after being infected with itch mites. This manifests itself in increasing itching, eventually pustules or papules can form.
Where do itch mites live?
The itch mites live only parasitically in the skin. To do this, they dig shallow pockets as young animals. The adult females build long corridors parallel to the skin surface, in which they lay their eggs. The tunnels are then sealed so that the larvae have to dig themselves back to the surface.
The mites therefore prefer to look for warm skin regions with a thin horny layer.
The mites and their ducts are particularly often found on the side of the fingers, wrists, armpits, buttocks, areola, navel, inner edge of the foot and on the penis. In children, they also like to dig into the palms of their hands and the soles of their feet. In principle, mite infestation is possible anywhere on the body.
Itch mites are mainly transmitted through prolonged and close physical contact between people, for example during sexual intercourse. Brief touches (e.g. shaking hands) are not enough for an infection, because the animals need 20 to 30 minutes to dig into the skin.
Sometimes itch mites from infected people find their way onto poster furniture, clothing or bed linen. However, they can only survive there for about 24 to 36 hours if the temperature is around 21 degrees Celsius. Such indirect contacts hardly play a role as a route of infection.
Can itch mites transmit diseases?
The itch mites do not transmit any infectious diseases. However, about four weeks after the infestation, a very unpleasant itching sets in, especially at night. The mites are found worldwide and can affect people of all ages. Last but not least, scratching the severely itchy areas of the skin can lead to so-called superinfections with bacteria.
What is special about the itch mite?
In and on the skin of healthy people, the number of mites rarely exceeds 40 individuals. If, on the other hand, someone has a weak immune system, many thousands of animals romp about on the patient. The problem with this is that the higher the number of mites, the higher the risk of infection.
If someone is infected with scabies and cannot be treated, the population living on them usually dies out after around 100 days. What remains is a lifelong immunity of the host against the mites - provided that its immune system is healthy.
In the past few years there have been repeated outbreaks in nursing homes and old people's homes. Because older and immunocompromised people often do not complain about the itching for a long time and can thus serve the mites undetected as a reservoir for further spread.
The Robert Koch Institute assumes that around 300 million people worldwide have scabies - there are neither estimates nor concrete figures for Germany.
Certain types of itch mite are also found in animals, where the disease is called mange. In the case of severe infestation, dogs, for example, lose large parts of their body hair.
How do I fight itch mites?
For treatment, creams or ointments with special active ingredients (for example permethrin, allethrin, ivermectin) are normally used externally. But there is also oral therapy. In principle, people who are in personal contact with infected people should also be treated.
Basically there is a close connection between the spread of scabies and hygiene: the more thorough a person is groomed, the fewer animals can be found on them. For example, textiles that have come into contact with infected people should be washed with hot water.
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