Bed Bug Symptoms

Bites are usually one of the first bed bug symptoms people notice. But bites alone are not enough to diagnose a situation as bed bugs. Not to mention that by the time you notice bite symptoms there may already be more than one generation of bedbugs living under your roof. Here you’ll learn the tell-tale signs of bed bug infestation, see pictures of what they look like find out how to inspect for them.

More photos of the common signs of bed bug infestation can also be found on the bed bug symptoms page in our bed bug picture gallery.

Important Note About Bed Bug Bites:

While they are usually the first thing people notice, bed bug bite symptoms are similar to many other insect bites and allergic reactions.

You simply can’t determine whether or not bed bugs are to blame without inspecting and detecting other symptoms and signs of bed bug infestation.  

Luckily, bed bugs leave behind 8 other signs of their presence...

4 Common Signs Bed Bugs Leave Behind

Bed Bug Symptom #1: Feces and Fecal Stains

When bed bugs take a blood meal, they defecate (poo) almost immediately.  That just adds insult to injury if you ask me! The stains left behind are often one of the first physical signs of bed bugs you will see.

live bed bugs and fecal stains on a bed sheetCredit: Dr. Harold Harlan/AFPMB (CC)

Bed bug feces ("poop") leave dark stains that look like a felt tip marker stain. The stain will often “bleed” into the fabric and look as if you went to bed with an open sharpie pen.

When you inspect for bed bugs, you may find stains like these on your pillow case or sheets or on the mattress itself.  

Fecal stains or actual droppings can also be found around the harborages where bed bugs are hiding when they are not busy feeding.  

Bed Bug Symptom #2: Blood Smears and Stains

Blood spots may also appear on the sheets or mattress. These stains are the result of engorged (blood-filled) bed bugs being crushed.  This usually happens if you roll over while they are feeding and they become trapped between you and the bed.

blood smears are a symptom of bed bugs crushed in the bedCredit: Lou Sorkin (CC)

You will usually find these kinds of stains on your sheets or pillowcases themselves. Occasionally you might also find stains like this on your pajamas as well.

The more of a restless sleeper you are, the more likely you are to find this symptom of bed bugs in your bed.

Note: Much like bites, blood stains alone are not enough to know whether you have bed bugs. They are just one piece of the puzzle.

Bed Bug Symptom #3: Shed/Cast Bed Bug Skins

As baby bed bugs (nymphs) move toward adulthood, they shed their skin a total of 5 times before reaching maturity – once at each new developmental stage. Cast skins look like lighter colored empty bed bug shells or casings – which is basically what they are. This picture of bed bug cast skins includes shed skins from multiple stages of the bed bug life cycle. The penny gives you a good sense of their actual size.

shed bed bug skins - next to penny to show actual sizeCredit: US Dept. of Agriculture/ (CC)

You are more likely to find these around harborages (bed bug hideouts) than out in the open like fecal and blood stains.

Bed Bug Symptom #4: Eggshells

Empty egg shells are certainly symptoms of a growing multi-generational bed bug population. They are very small – about 1 mm in length - but visible to the naked eye - a magnifying glass helps.

They look like dried out casings of live bed bug eggs (see close-up of bed bug eggs below) but are less shiny and may be somewhat flattened.

eggs like these are a symptom of bed bug infestationCredit: Dr. Harold Harlan/AFPMB (CC)

They will be found in the places where bed bugs hide, especially on rough surfaces like fabric or wood.

See their actual size in this video on the bedbug life cycle page.

While none of the above symptoms of bed bugs are proof of a currently active infestation, bed bugs don't go away on their own.  So treat them as definite clues to their presence - but don't stop there.  You need proof of LIVE bed bugs to confirm your infestation.

Never start any (DIY or professional) bed bug treatment without proof of LIVE bed bugs. You can read more about this in 8 things you should expect from your bed bug exterminator.

4 Signs of Active Bed Bug Infestation

Bed Bug Symptom #5: Bed Bug Eggs

Credit: Dr. Harold Harlan/AFPMB (CC)

Bed bug eggs are shiny translucent to pearly white in color and are found both in bed bug harborages and locations away from the main population (female bed bugs tend to lay some eggs “away from the crowd”). They have a sticky film when they are first laid to help them adhere to surfaces and this can give them a kind of shiny appearance. Bed bug eggs are approximately 1 mm long.

They are more often found on wood and fabric than on plastic or metal.

Bed Bug Symptom #6: Nymphs

Credit: Lou Sorkin (CC)

Baby bed bugs, called nymphs, are smaller and lighter colored than adults. They can be almost clear until they are fed at which point they turn blood red.

Credit: Lou Sorkin (CC)

Depending on the developmental stage, they range from the size of a pin-head or poppy seed size at birth to about ¼” as they reach maturity. 

Nymphs are sometimes the first live bugs that will be found because they tend to feed more frequently than adults – as often as once a day. Learn more about baby bed bugs on the on the bed bug life cycle page.

Bed Bug Symptom #7: Adult Bed Bugs

Adult Bedbug with scale for actual sizeCredit: CDC (PD)

Fully matured bed bugs are a rusty-brown color and very flat – until they've filled their bellies with blood. They are approximately ¼” in length – about the size and shape of a small apple seed.

As the feed they swell up (become engorged) and become more elongated and turn a dark purplish-red color.

Adult Bed Bug on a DimeCredit: MedillDC/NPMA (CC)

In the early stages of an infestation, you are most likely to find them in around the seams, piping and tufts of your mattress and box spring or in cracks and crevices on the headboard and bed frame. See more pictures of bed bugs in furniture...

close-up view of bed bugs and fecal stains on mattressCredit: Lou Sorkin (CC)

As time passes and the infestation grows, they tend to spread out from the immediate feeding area. Because they are so flat, they can hide in the most surprising places.  Read about where bed bugs hide here.

More in depth information about what bed bugs look like in all stages of their life cycle can be found on the bed bug life cycle page.

Bed Bug Symptom #8: Distinctive Odor

Bed bugs have a sweet musty smell, which some people have said smells like coriander, almonds or nearly over-ripe raspberries. I think its kind of a pungent, sickeningly-sweet smell and would lean more toward the almost rotting raspberry description. The smell is more obvious in heavier infestations or where the bugs have become agitated. Smelling them is not a reliable way to confirm a bed bug infestation, but their distinctive scent does allow bed bug sniffing dogs to pinpoint their hiding places effectively when visual evidence is not easily found. 

If You Think You Might Have Bed Bugs...

It's time to get down to business and do your own inspection. It will take a little time and effort, but it’s not as hard as you might think.  

No worries! I’ll walk you through how to find bed bugs in your home or hotel room step-by-step

IMPORTANT NOTE: Bed bugs are very skilled at hiding. So failure to find signs of an active bed bug infestation is NOT proof that they aren't there.  

If you come up empty after following the bed bug inspection tutorial, consider using alternate methods of detecting bed bugs. I also really recommend calling in a qualified exterminator to do a professional inspection. 

Knowing the symptoms of bed bug infestation is the key to diagnosing a suspected problem.  Even if you’re just looking to prevent bed bugs from coming home with you when you travel, being able to identify the signs of a bed bug infestation is a skill you can’t afford to go without.

If you found something, but it's not a bed bug, you can get help here.

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