Bed bugs

Red spots on the arms, legs and face could be bites from bed bugs. These parasites feed on human blood. Their bites may be itchy but are harmless.

At a glance

  • Bed bugs are small parasites that feed on human blood.
  • Their bites are itchy and can be easily confused with insect bites or flea bites.
  • While bed bugs are bothersome, they are harmless and do not transmit any diseases.
  • Bed bugs spread through contact with infested clothing, luggage or mattresses and bedclothes.
  • There are various treatments to get rid of bed bugs.

Note: The information in this article cannot and should not replace a medical consultation and must not be used for self-diagnosis or treatment.

Bed bugs on human skin

What are bed bugs?

Bed bugs are oval, flat parasites that are just five millimeters in size. These brownish insects like the dark and, in the daytime, they hide in dark places, such as mattresses and bedclothes or cracks and crevices. This makes them difficult to find.

At night, bed bugs crawl over sleeping humans and feed on their blood. Their bites sometimes itch and can become inflamed. However, bed bugs do not transmit disease.

Bed bugs go through six stages of development from egg to adult insect. They need a meal of blood every 3 to 5 days to do this. They can multiply and spread very quickly.

What are the signs of bed bug bites?

Often, people don’t initially notice that they have been bitten. This is because bed bugs bite at night while the person is sleeping.

The following symptoms may indicate a bite from bed bugs:

  • itchy bite sites or weals, especially on the arms, legs and face
  • several bites are sometimes found directly beside each other
  • itching, which often only starts a few days later
  • fitful sleep
  • blood stains on bed sheets
Often, treatment is not required for bed bug bites and hives. They usually disappear after about a week.

Where do bed bugs come from?

Bed bugs are typically transferred via clothing and luggage. Any bed bugs hiding in mattresses or other pieces of furniture also find their way to humans.

The risk of coming into contact with bed bugs is particularly high in accommodation that is used by lots of people, such as a youth hostel. Bed bugs are also more likely to thrive in places where lots of people live closely together.

How common are bed bugs?

Bed bugs are common all over the world. Bed bugs can spread through travel and trade.

Interesting fact: Many pests have now become immune (resistant) to insecticidal chemicals (insecticides). This means they spread more easily and it becomes more difficult to get rid of them. For this reason, pest control experts often use a combination of several active ingredients to deal with a bed bug infestation.

What can be done to prevent bed bugs?

Those who are sleeping away from home can check things such as bed linen, mattresses and furniture near the bed for the presence of bed bugs. As bed bugs hide themselves during the day, they are often difficult to find. Small dark spots (bed bug feces) or blood stains on bedding indicate an infestation. If the bed bug population has already reached a substantial number, there may also be a sweet, musty odor.

Used mattresses, clothing or furniture should be checked for a bed bug infestation before they are brought into the home.

Effective means of repelling bed bugs by simply using a certain smell (i.e., a repellent) are not yet known.

How are bed bug bites diagnosed?

People initially notice red spots on the arms, legs and face on waking. These are bite marks from bed bugs. There are often several bites directly beside each other.

The bites may be itchy but this isn’t always the case. Sometimes the itching only begins days later.

Important: Bites from fleas, mites or mosquitoes can be confused with those from bed bugs.

Other possible reasons for itching and red spots on the skin include allergies, eczema, chickenpox or bacterial infections such as impetigo (Impetigo contagiosa). These need to be ruled out by a doctor.

The diagnosis is absolutely certain if bed bugs are actually found.

How are bed bugs and their bites treated?

Those who discover bed bugs should act fast so that the parasites don’t multiply and spread any further.

Bed bugs are sensitive to temperature. They die off at a temperature of around 50 degrees Celsius or higher or if they are frozen for at least 5 days at a temperature of minus 5 degrees.

The main steps to take immediately include:

  • disposing of heavily infested mattresses or furniture
  • washing bedding and clothing at a minimum temperature of 60 degrees and drying them in a dryer at a high temperature
  • freezing delicate clothing and small items in sealed plastic bags for several days
  • cleaning less infested furniture and floors with a vacuum cleaner and then sealing the vacuum bag inside an airtight plastic bag before disposing of it
Important initial measures to combat bed bugs: dispose of heavily infested mattresses or items of furniture, wash bed linen and clothes at 60 degrees Celsius, vacuum clean furniture and flooring

The home and furniture can also be treated with insecticides. However, this task should always be left to a specialist company, as it will take all the necessary precautions to prevent any harmful health effects, such as poisoning. After 4 to 20 days, the treatment should be repeated to ensure that all bed bugs are actually caught.

Treatment with heat can also be carried out. In this case, the infested rooms are sealed up by professionals and heaters are set up to heat the rooms at more than 50 degrees for at least 48 hours.

Often, treatment is not required for bed bug bites and hives. They usually disappear after about a week. If the bed bugs have bitten a person repeatedly, the bite sites may itch more. Non-prescription or prescription-only products such as cortisone ointments relieve the itching. Used once to twice daily for 7 days, they promote healing of the affected areas of the skin.

More detailed information about getting rid of bed bugs can be found at

In cooperation with the Institute for Quality and Efficiency in Health Care (Institut für Qualität und Wirtschaftlichkeit im Gesundheitswesen) (IQWiG).

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