Scabies

The main symptom of scabies is severe, often agonizing itching that is usually worst at night. It itches because the body’s immune system is reacting to the mites and their excretions. Sometimes, parts of the body that aren't directly affected by the scabies mites will also be itchy. A rash on the skin is another typical symptom. It might include

• slightly raised, visible patches or thread-like lines (mite burrows),
• redness,
• bumps, and
• blisters.

If the itchy patches are scratched open, people often have small wounds too.

The symptoms usually appear about two to five weeks after infection. If you become infected again, the symptoms appear a lot sooner.

People who put a lot of effort into skincare – in other words, wash and moisturize their skin particularly thoroughly – might not notice the rash very easily. But good physical hygiene does not prevent infection.

Scabies mites tend to prefer areas where the skin is particularly thin. These include the areas between the fingers and toes, the sides of the hands and feet, the wrists, inside of the elbow, hollow of the knee, armpits, the area around the nipples, the belly button area, the bottom, and the penis. Babies, toddlers and people with weakened immune systems may also have the rash on their head, neck, trunk of the body, nails, palms of the hands and soles of the feet.

Scabies is caused by tiny parasites that live on or in the skin. At a size of about 0.3 to 0.5 millimeters, female scabies mites can just about be seen as a small dot. Male mites are even smaller, and stay on the surface of the skin.

Fertilized ("pregnant") females look for a thin patch of skin and burrow into the top layer. They then burrow paths up to one centimeter long, lay up to four eggs a day, and leave droppings.

A cycle begins: Larvae hatch out of the eggs and mature in the skin. When they are sexually mature, they crawl to the surface of the skin, pair up, and reproduce. Usually only about 10 to 15 adult mites live in or on human skin at any one time.

Female scabies mites in the skin can live to be about four to six weeks old. But outside the human body, at normal room temperature, they usually die after one to two days. Male mites die after fertilizing a female.

Scabies mites can’t jump or fly. You can only catch scabies from someone if you have skin-to-skin contact with them for about 5 to 10 minutes. That is why scabies often spreads within families or between partners, during activities like breastfeeding, cuddling, playing or sleeping in the same bed. People who care for somebody who has scabies can also become infected. Brief contact like shaking hands or hugging someone is usually not enough for it to be passed on. The more mites there are on the skin and the longer the skin contact is, the higher the risk of becoming infected.

Adults often pass on scabies during sex. As a result, sexually active people who have several different sexual partners are at greater risk of infection.

Scabies mites can also be passed on despite good physical hygiene. But poor hygiene is still a risk factor.

Scabies can affect people of all ages. But the risk varies depending on where you live and the climate there:

• In moderate climates, scabies is more common during the colder seasons.
• Scabies mites are widespread in countries with a tropical climate, especially among people who live together in small spaces with poor hygiene conditions.

Scabies is less common in Europe. It is most prevalent here in children and their mothers, people with weak immune systems, and adults who are very sexually active. There are sometimes also scabies outbreaks in communal facilities like retirement homes and nursing homes, residential homes, and hospitals.

The symptoms of scabies only appear a few weeks after infection. But you can already infect others before having symptoms yourself.

Scabies usually becomes chronic if left untreated. That means you have it permanently and it doesn't go away on its own. In rare cases only, the mites disappear without treatment after several years.

The itching in particular can make it difficult to concentrate and sleep well. Some people feel disgusted or ashamed too.

Scratching can lead to small wounds on the skin, which bacteria can easily get into. If they spread, they can cause a bacterial infection on top of the scabies infection. The skin then becomes very red and weeps, and pus and scabs sometimes also form.

People with a weak immune system and older people may get a particularly severe form of scabies called crusted scabies (Scabies crustosa). It leads to large patches of red skin that are covered in thick scales and crusts. Because there's a weaker immune response, it causes hardly any itching, or none at all. Crusted scabies is especially contagious because a lot of mites live in and on the skin.

If you have itching and any of the typical skin symptoms described above, it could be scabies – particularly if you have been in contact with someone who has scabies. It is then important to see a doctor.

Doctors can usually diagnose scabies by looking at the skin and asking about the other symptoms.

To make sure, they can use a special magnifying glass with a light on it (a dermascope) to look for mites. A microscope examination is also possible: The doctor picks open an affected area of skin using a fine needle, or scrapes off a thin layer of skin. Mites and their eggs and droppings can already be seen under a microscope before the rash appears.

If there's no reason to believe that any of your close contacts have scabies, it is neither necessary nor possible to prevent infection. Things like washing your hands and using disinfectant or condoms do not stop you from catching scabies.

If you have scabies yourself, the main thing is to make sure you don't pass it on to other people. It is important to only have skin-to-skin contact and sex once you have finished your treatment.

Sometimes, people already infect others before they realize they have scabies themselves. Because of this, it's important to inform people who you have had close contact with. They can then be checked for symptoms and get treatment if needed.

Scabies mites rarely get on to someone's skin through shared bedding, towels or clothing. It is also rare to become infected again in this way, but it is possible. To prevent that from happening, various hygiene measures can be taken:

• Wash used, washable textiles at 60 degrees Celsius (140 degrees Fahrenheit).
• Store non-washable items such as slippers or soft toys in a warm, dry place in sealed plastic bags for three to four days, or in the freezer (at minus 10 degrees Celsius, or 14 degrees Fahrenheit) for at least five hours.
• Vacuum upholstered (soft) furniture, pillows, mattresses, carpets and car seats, and don't use them for three days.
• Clean all washable surfaces.

The aim of treatment is to kill all the mites and their eggs. Your doctor will prescribe the medication to do that. It is available as creams and as tablets.

The standard treatment is a cream containing the drug permethrin. It is best to put it on your whole body from the chin down in the evening and leave it on the skin overnight for at least 8 hours, but preferably for 12 hours. Once it has been left to take effect over night, you can shower and wash as normal the next morning. Experts recommend repeating the treatment after seven to ten days. If the cream doesn't kill the mites or isn't an option for other reasons, it's possible to take tablets or use other creams.

The especially contagious type of scabies known as crusted scabies is treated using a combination of tablets and creams.

Following the first treatment, you are usually no longer contagious after 36 hours. It is normal for your skin to still itch and be red for a few weeks afterwards, though. These symptoms can be treated using anti-pruritic (itch-relieving) tablets or anti-inflammatory creams for a short while. If the symptoms still don’t get better after a second round of scabies treatment, it's important to see your doctor again.

It is best for close contacts like family members, people in the same household and sexual partners to have treatment at the same time. That can prevent you infecting each other over and over again.

When people are ill or need medical advice, they usually go to see their family doctor first. In our topic "Health care in Germany" you can read about how to find the right doctor – and our list of questions can help you to prepare for your visit to the doctor.