What is the main cause of dermatography

scabies

Scabies is a contagious skin disease. It is caused by scabies mites. The female mites drill into the horny layer of the skin and dig tunnel-like passages there, which is why they are also called burial mites. These parasites specialize in humans and can spread to other people through prolonged skin contact. Scabies often causes excruciating itching - but it can be treated effectively.

At a glance

  • Scabies is a contagious skin disease caused by a special genus of mites: the scabies or burial mites.
  • The female mites dig tunnel-like passages in the upper layer of the skin and lay their eggs there.
  • The body's immunological defense reaction is associated with eczema.
  • Severe itching is typical and increases at night.
  • Scabies can be treated with ointments or tablets.
  • To avoid re-infection, all relevant contact persons must be treated at the same time.
  • Mere handshakes or brief touches usually do not lead to infection, but the risk of infection increases with the duration and extent of physical contact.

Note: The information in this article cannot and should not be used as a substitute for a doctor's visit and should not be used for self-diagnosis or self-treatment.

What is scabies?

Scabies is a contagious skin disease caused by mites. The female mites drill into the upper layer of the skin and leave their eggs and excretions there. This leads to an eczema reaction. Typical of scabies is severe itching, which is particularly noticeable at night.

The medical term for scabies is scabies, derived from the Latin word “scabere” for “to scratch”. Scabies can be effectively treated with medication: These so-called scabicides are usually applied to the skin as creams or ointments.

What are the symptoms of scabies?

On average, it takes 2 to 5 weeks before an itchy eczema reaction occurs after an initial infestation with grave mites. However, an infected person can infect others before symptoms develop. In the case of repeated infection, the symptoms set in after a few days, because the body is sensitized - so it already knows the parasites - and therefore reacts more quickly with an immunological response.

Scabies is characterized by severe itching, which sometimes affects the whole body and increases during the night due to the warmth of the bed. The itching is accompanied by a rash, which is characterized by small nodules and vesicles. This itchy eczema is an immunological reaction to the mite infestation.

The mite ducts can initially be recognized as fine, irregular papules (elevations) on the skin that are up to one centimeter long and, due to their curved shape, resemble a comma. They are not always easy to spot with the naked eye; the mites themselves can only be seen with a microscope or certain magnifying glasses (dermatoscope).

The corridors are often found:

  • between fingers and toes
  • on ankles, wrists and elbows
  • on the penis
  • on armpits, nipples and on the navel
  • in the groin and buttocks

The hairy head, face, and palms of the hands and feet can also be affected rarely, especially in babies and toddlers.

Even people with a weakened immune system often develop a particularly contagious form of scabies, in which extensive, flaky reddening and thick crusts develop on the skin. One speaks here in particular of the bark scabies (Scabies crustosa). The otherwise typical itchiness is sometimes missing in this form of the disease. Because of the abundance of mites, even brief skin contacts or even contact with objects used by the person concerned are contagious.

How do you get infected with scabies?

Scabies is mainly transmitted through direct skin contact. Since the itch mites move very slowly, continuous and extensive contact for at least 5 to 10 minutes is required, for example when playing, cuddling or sleeping in the common bed. Mere handshakes or short hugs, on the other hand, usually do not lead to infection.

An exception is the scabies crustosa, in which the skin of the patient is colonized with thousands or even millions of the parasites. Here, under certain circumstances, a brief skin contact or contact with detached skin flakes is sufficient to become infected.

In addition to the human-specialized scabies mites, there are other types of mites that infest pets. These mite diseases in animals are known as (animal) mange.

The animal mites occasionally pass on to humans, but die quickly on human skin without multiplying there. The skin irritations that they sometimes cause ("pseudo-scratches") usually go away on their own after a short time.

Important to know: Outside the skin, the itch mites, which specialize in humans, can only survive for a maximum of one to two days. In addition, they die within 10 minutes at a temperature of 50 degrees - for example in the washing machine. A disease transmission through clothes and underwear is rare in practice, with the exception of bark scabies.

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How common is scabies?

Scabies occurs worldwide in all age groups. However, children are particularly often affected as well as sexually active people with changing partners. Elderly people or people who take drugs that weaken the immune system are prone to highly contagious bark scabies.

Outbreaks of scabies can also occur in community facilities such as kindergartens, old people's and nursing homes, hospitals, shelters for the homeless or prisons.

However, there are no reliable figures on how common this parasite infestation is in Germany as a whole, because there is no comprehensive reporting requirement. However, scabies is one of the most common infectious diseases and is likely to affect many thousands of people in this country every year. This is suggested, among other things, by a study by the Robert Koch Institute on the incidence of the disease in 2016. The incidence of the disease may fluctuate from region to region over the course of many years.

How can you prevent scabies?

Itch mites are often passed unnoticed to other people before the disease breaks out. In such cases it is hardly possible to prevent infection.

If, on the other hand, the disease has already been diagnosed in a patient, close contact persons should be examined and, if possible, all treated at the same time. If physical contact with the sick cannot be avoided, for example when caring for relatives, long-sleeved clothing and disposable gloves offer protection.

So that the mites do not spread through objects in a shared household, the infected person's clothes and towels should be washed daily at at least 50 degrees, the beds freshly made and upholstered furniture vacuumed with a powerful vacuum cleaner.

Contaminated objects can also be stored in sealed plastic bags for 3 days at at least 21 degrees, for example near a heater, or frozen for 2 hours at minus 25 degrees. This causes the itch mites to die.

People suffering from scabies or who are suspected of having it are not allowed to visit or work in community facilities such as schools or kindergartens until the end of treatment.

How is scabies diagnosed?

Experienced physicians or dermatologists can often recognize scabies based on the typical symptoms and a physical examination and confirm the diagnosis by detecting the mites in scraped skin particles under the microscope or by means of an incident light microscopy (dermatoscopy). Laboratory tests are not necessary to diagnose scabies.

How can scabies be treated?

Scabies can usually be treated well with medication that is applied topically to the skin. The active ingredient permethrin is mostly used here. Alternatively, for example, crotamiton can also be used. It is also possible to take tablets with the active ingredient ivermectin in certain cases of illness.

Even after a thorough one-time treatment with permethrin - for example by applying an ointment overnight - or 24 hours after taking ivermectin, a sick person is usually no longer contagious. Ivermectin should not be used in pregnant women or young children.

After the treatment, the itching will subside within 1 to 2 weeks.

However, repeated treatment and prolonged avoidance of unprotected contact are necessary for scabies crustosa.