Body Lice vs. Bed Bugs: How to Tell the Difference

Body lice and bed bugs are related parasites and they feed on human blood. It is important to tell the difference between these two types of parasites, so as to be able to get suitable treatment and eliminate the parasites from your home and environment.

Body Lice

The body louse (Pediculus humanus humanus) feeds on human blood and will cause extreme itchiness and discomfort. The body louse may survive up to 30 days in a suitable environment and can be eliminated through boiling infested clothes and bed linen.

Bed Bugs

Bed bugs are a small parasite from the Cimicidae family. Bed bugs feed on the blood of humans and will be mostly active during nighttime. During daytime, bed bugs stay hidden in furniture, mattresses or rugs.

How to Tell the Difference between Body Lice and Bed Bugs

The differences between body lice and bed bugs are subtle; however, it is essential to identify the lice or the bed bugs. You should look at the size, color, odor and the bite marks. Body lice may be felt during day time, as they will get attached to clothes or skin; bed bugs will be felt mostly during the night or when sleeping in the infested area.


Body lice are smaller in size than bed bugs; body lice are on average 3 to 4 mm (the size of a sesame seed), while bed bugs are 6 to 9 mm before feeding. Lice and lice nits may be visible, especially if you use a magnifying glass; however, bed bugs tend to hide and are more difficult to spot. Bed bugs may be detected during nighttime using a flashlight.


The color of the body lice may be gray or transparent, while the color of bed bugs is brown; however, once the body lice are filled with blood, they will also have a brown color.

Bite Marks

Take a look at the bite mark; the body lice will leave a single bite mark (there may be other marks on the body) whereas the bed bugs will cause a series of 3 or more linear bite marks. Lice cause itchiness, while bed bugs will only cause itchiness in more sensitive people that react to the bed bug saliva.

The bed bugs will also leave a dark brown or black mark on the bed linen. These marks are actually excrement (digested blood) left by bed bugs. Bed bugs may also cast their skin, so you can also detect their skins in the bed or neighboring areas.

Bed Bugs and Foul Odor

If the bed bugs are numerous, the home will have a foul odor, which is caused by the oils secreted by the bugs. Typically, body lice don't have a specific odor.


The transmission of body lice is through direct contact with an infested person or by sharing clothes or bed linen with an infested person. Bed bugs can only be transmitted through sharing clothes or bed linen.

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