Signs of Bed Bugs

Knowing what signs of bed bugs to look for is the first step in identifying whether you have bed bugs.   Adult bed bugs are 1/4 to 3/8 inch (4-5mm) long, brownish-red rust in color, with a flat, oval-shaped body.  Young bed bugs (also called nymphs) are smaller and lighter in color.  Because these insects are nocturnal (they feed primarily at night), it makes infestation detection difficult.  So the questions are, where do you look for bed bugs, and what do you look for?

Research shows that 85% of bed bugs are found in or near the bed.  When looking (inspecting) for signs of bed bugs and their infestation, most of your search efforts should be focused on the wooden headboard, bed frame, in the seams, or inside the mattresses/box springs.

Get Rid of Bed Bugs Guide

Since bed bugs prefer fabric or wood surfaces to metal or plastic ones, the remain­ing 15% of infestations will usually hide in upholstered furniture (other than beds/headboards), bedroom cabinets, under loose wallpaper, behind wall hangings, baseboards, cracks in wood molding, rugs and under the tack board of wall-to-wall carpeting.  If there is a heavy infestation, bed bugs have been found inside radios, phones, clocks, television sets, smoke detectors, and in clutter strewn about.  They could even migrate to adjoining rooms.

Although you can see the adults and accumulations of nymphs with the naked eye, it is best to use a flashlight and magnifying lens to find the smaller and harder to see eggs. 

What do you look for?

When looking for signs of bed bugs, it’s important to be familiar with the telltale signs that bed bugs leave so you know what to look for when inspecting for an infestation.  Remember that the only way to be 100% certain that you have bed bugs is to collect a physical sample of a bed bug or its eggs and have a qualified pest management professional examine it.  These insects have existed for centuries; just because you couldn’t find them doesn’t mean they aren’t there. For more detailed information about what bed bugs look like, see the bed bugs page’s pics.

Bed bug bites

Bite symptoms are a good indicator that you might have bed bugs, but do not automatically assume that any bite-like mark is a bed bug bite.   100% certainty that the bite is from a bed bug is difficult to diagnose as the bites cannot distinguish between the bites of other arthropods (invertebrate animals) such as spiders, centipedes, fleas, and mosquitoes.  The first signs of bed bugs and most common confusion is that the red, itchy bed bug welts are mistaken for mosquito bites.

Bed bugs tend to leave welts in straight rows of 2 – 3 bites and are typically found on the arms or shoulders.  This is because they will feed (bite), digest, move a little farther and feed (bite), digest, move a bit farther and feed (bite) again in a straight line.  Some experts referred to this formation as the bed bugs “breakfast, lunch and dinner” trail.  The bite marks look like little red bumps, similar to mosquito bites but longer, that can swell up to 20cm in diameter.  The bites are painless at first but later turn into itchy red welts.

An important note is that medical professionals cannot give a positive diagnosis simply by examining the bite symptoms.  The best they can do is suggest possible explanations for what may have caused the bites/symptoms.

Other tell-tale

Aside from spotting the bed bugs themselves, the next best way to see signs of bed bugs and their infestation is by search­ing for their fecal spots, eggs, egg cases, shed skins (exuviae), and smell.

Fecal Spots

Bed bugs defecate partially digested blood that looks like dark brown or black “fecal” spots around where they live.  That is why you will see unsightly small, round, black spots in known bed bug hiding places like seems in box springs, mattresses, bedsheets, furniture, and any other bed bug-infested place.  These unsightly “fecal” spots will not dry up and flake off if rubbed.  If you wipe them with a damp rag or cloth, the spots will smear.

Blood Stains

It is presumed that since bed bugs live off the blood that you will see red bloodstains.  Unfortunately, the only way you will see any red spots is if a bed bug was crushed after a recent undigested feeding.  It’s the same as swatting a mosquito that is full of blood after feeding.

Eggs/Egg Cases

The eggs and egg cases are very tiny, the ball’s size in a ballpoint pen, making them hard to detect.  If you see these signs of bed bugs, they aren’t far away, and their numbers are growing.

Shed Skins

Bed bugs molt and shed their skins (exoskeletons), leaving behind their old light-colored exoskeleton husks (exuviae).


Bed bugs have stink glands that leave a foul, musty, rotting-meat smell behind.

If you see any of the above tell-tale signs of bed bugs and bite symptoms, the chances are excellent that they are nearby.

Using dogs to search for signs of bed bugs

Recent research has shown that specially trained dogs are an effective method in finding bed bug infestations.  Field and laboratory tests that used dogs for the bed bug search were 97% effective in identifying the infestation.

This article has provided you with the information to detect signs of bed bugs and their infestations.
Patience and perseverance are your best tools in finding low-level bed bug infestations.  This is a problem that you can take on and win by yourself.  Always consult with a qualified bed bug pest management professional to be 100% sure that you have properly identified bed bugs as your culprit.

Now that you know what the signs of bed bugs are, it is time to find out how to get rid of bed bugs yourself.

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