How Do I Know if I Have Bed Bugs?

7 Common Signs of a Bed Bug Infestation

Article by Joseph Salvatore Knipper

If you’re reading this article, it’s at least crossed your mind that you might get bed bugs someday. How would you know, though?

Pests tend to be small and good at hiding. If bed bugs were large enough that they needed to ring the doorbell in order to infest your apartment, they wouldn’t be a problem.

Despite their general sneakiness, bed bugs do leave signs of their presence. In this article, I will review 7 signs of a bed bug infestation, ranked in order of how much certainty they can provide.

In general, all the signs require professional confirmation to be certain, but this article will give you an idea of when to seek out that professional confirmation.

Here are seven signs of a possible bed bug infestation, starting from #7:

#7: Odor

Raspberries, which are often compared to the smell of bed bugs

Bed bugs emit pheromones which present a slightly-sweet, musty odor. It is often compared to raspberries, but descriptions vary; some say it even smells like coriander.

However, this is the least helpful indication of bed bugs (unless you are a bed bug canine). That’s because the odor produced by individual bed bugs is almost imperceptible to the human nose.

By the time you actually notice the smell, it means that the infestation has already become severe… to the point where you’ve likely already found live bed bugs.

#6: Bites

Image of bed bug bites on a person's back

This is many people’s first indication that something might be off; bed bugs prefer to feed off us when we sleep, thus bites can appear on skin that is exposed during the night.

However there are many misunderstandings about bed bug bites that make them a less-than-reliable method of detection unless used in conjunction with the other signs.

Firstly, you may have heard that bed bugs bite in a straight line of 3 bites (typically called “breakfast, lunch, and dinner”). True, this pattern can occur with bed bugs; they may have to bite a second or third time to find the right spot. However, a bed bug may also get a full meal on the first try. Thus, you may have bed bugs without the “breakfast, lunch, dinner” pattern appearing.

Secondly, the reaction to bites may not be immediate. Bites become itchy from an allergic reaction to the bed bugs’ saliva, but this reaction may be delayed by hours or even days. The mystery welt that appears in the middle of an outdoor party may be from a bed bug’s snack two nights ago, or it may just be a mosquito.

Thirdly, everyone reacts to bed bug bites differently. While most people get small, flat, itchy, reddish welts, some people react more severely. I heard of one man who got golf-ball-sized welts from his bites, though this is rare. Many people may not react at all.

#5: Rusty stains on your sheets

image of rusty bed bug blood stains on a sheet

(Photo Credit: David Albers)

Even if their host is unaware of their presence, bed bugs don’t always get away unscathed. If you suddenly shift in your sleep you can crush a bed bug who has just fed, leaving a rust colored stain on your sheet.

If you see something that might be a bloodstain on your sheets, check your body for a zit or scab that might be the cause. If you can’t find another explanation (or if you see new stains frequently), start looking for the other signs.

#4: Fecal marks

image of bed bug fecal marks staining a bedsheet

(Photo Credit:

Compared to the blood stains we just mentioned, bed bug fecal marks are much smaller.

These small dark spots resemble a dot from a pen or marker. They are typically about 2-4 times the size of the period at the end of this sentence.

Because bed bugs only eat blood, their fecal marks smear in a very distinctive fashion. Bed bug fecal marks can be quite difficult to wash out, and water will cause them to resemble “magic marker stains” on fabric.

#3: Eggs

bed bug eggs appearing as small grains of rice

(Photo Credit:

Pregnant females lay 1-7 eggs a day. Eggs are about 1 mm long, pearl white, and ovular — like tiny grains of rice around the size of a pinhead. According to the EPA, they can be “marked by an eye spot if more than five days old.”

Eggs are usually loosely stuck in crevices of fabric or wood, though really they can be anywhere. Females wander once pregnant, which can sometimes spread the infestation to neighboring apartments.

Because eggs are so small, they are easy to miss. Still, a cluster of white ovals with eye spots stuck to the underside of your bed frame is a likely indication of a serious bed bug problem.

#2: Shell Casings

bed bug shell casings, also known as husks or skin casings

(Photo Credit:

Bed bugs go through 5 life cycle stages before they reach adulthood. Before they proceed to each stage, they must feed on a blood meal and shed their exoskeleton, creating what we call “shell casings”.

Abandoned shell casings, also known as “husks” or “skin casings,” are an early sign of a growing bed bug infestation.

These translucent, hollow outlines of juvenile bed bugs are often easier to find than the bed bugs themselves. They can be anywhere that bed bugs hatch and breed — check mattress eams, upholstered furniture, and in holes, cracks, and crevices within wooden furniture.

#1: Live Bed Bugs

live bed bug found during canine bed bug inspection MMPC

(Photo Credit: MMPC)

Finally, the most obvious sign. You’d think finding a live bug would be a smoking gun, but it’s not that simple.

First, bed bugs don’t wander around unless they are seeking food, or unless they are already pregnant females avoiding overzealous males. They tend to find a hiding place and stick to it. For this reason, many people never see live bugs until the infestation becomes severe. Bed bugs are often found only during a move because packing disturbs their hiding places.

Secondly, many insects are often confused for bed bugs. However, here are some quick tips for identifying adult bed bugs.

Adult bed bug up close

Tips for Identifying Adult Bed Bugs

  • Bed bugs have small vestigial front wings but cannot fly. If it flies, it’s not a bed bug.
  • Bed bugs have a narrow head and thorax with a wide abdomen.
  • Adults are flat and brown/rusty colored, while nymphs are pale. Once fed they elongate slightly and turn reddish.
  • They have 6 legs and 2 antennae. The antennae have 4 segments.
  • Bed bugs tend to hide in the joints of furniture, the seams of mattresses, and the folds of curtains. They are also common in the cracks behind bureau drawers, baseboards, and bed frames. Check for bugs, eggs, shell casings, and fecal stains in these areas.
  • Bed bug indicators (also called monitors or interceptors) can also be a way of testing if you have an infestation.

Still not sure? MMPC offers a free Pest Identification Service, so you can simply send a picture of any of the above signs and we will get back to you within a business day to help you confirm if you may have bed bugs. We are also happy to answer any of your questions (free of charge) and provide recommendations for next steps.

Bed bugs are a heavy burden to bear, and getting rid of them is a team effort. Hopefully, you now have a better idea of when to call in that team.

For more Information please see MMPC’s resource page.

Bed Bug Resources: