All You Need To Know About Bed Bug Shells, Skin and Molting

When we think about having a bed bug infestation, we think about waking up to a body full of red bites and welts. However, these physical marks might not be visible due to a number of reasons, which is why everyone should know about the other signs that might signal an infestation, including the presence of bed bug shells or casings. These shells are actually the bug’s exoskeletons, sloughed off during molting, and it is a big indication that you have a thriving bed bug infestation.

This guide is not meant to gross you out but is intended to help you identify signs and the extent of the bed bug infestation, so that you can combat it. Here, you will learn about:

  • What are bed bug shells or casings?
  • The lifecycle of bed bugs.
  • What do bed bug shell looks like?
  • How often do bed bugs shed their skin?
  • Some common places where you can find bed bug cast skin.
  • Does finding bed bug skins means you have an infestation?
  • What should you do if you discover bed bug casings?

What are Bed Bug Shells or Casings

Bed bug shells, casings, and exoskeleton are all different names for the same thing. Like many insects, bed bugs have an exoskeleton on their bodies. This exoskeleton is made up of a substance called chitin and is used to support and protect the insect’s body. However, it does not keep growing, like the insect’s body. Which is why, bed bugs have to shed it or molt, at different stages of their lives. A shed exoskeleton is known as casing or a shell.

Bed bug nymph stage

Lifecycle of Bed Bugs

To understand the implications of bed bug casings, we must first understand the lifecycle of bed bugs.


Adult female bed bugs lay white, oval and translucent eggs into tiny spaces, soon after mating. These eggs are one-sixteenth of an inch long and can hatch in 6 to 10 days. A female can lay as many as 200 to 250 eggs in her lifetime. When these eggs hatch, they leave behind empty white casings.

1st Stage Nymph

There are five stages of the nymph stage that bed bugs undergo before they reach full maturity. The 1st stage nymphs are 1.5 millimeters in length. When these nymphs hatch from their eggs, they start looking for their first blood meal.

2nd Stage Nymph

A bed bug will undergo molting after having its first blood meal. Once it has shed its exoskeleton, it will be about 2 millimeters long.

3rd Stage Nymph

The bed bug will continue to feed and will undergo molting once again, after the second molting, it will be about 2.5 millimeters long.

4th Stage Nymph

In the 4th stage, a bed bug will be about 3 millimeters long.

5th Stage Nymph

This is the last stage of the nymph, after which the bed bug will turn into an adult. The bed bug will undergo its last molting and will emerge from it about 4.5 millimeters long.


The whole process of a nymph becoming an adult takes about five weeks. Adult bed bugs do not molt and will not grow anymore. This is the stage where a bed bug is able to breed. Usually, an adult bed bug can live for two to four months. However, sometimes they can even survive to up to a year.

What Do Bed Bug Shells Looks Like?

A shed bed bug exoskeleton looks almost exactly like a live bed bug. The bed bug skin remains undamaged, and it seems like the entire insect has somehow magically slithered out of the shell. However, as the skin is empty from the inside, it appears translucent.

The type of bed bug casing will depend on the stage the nymph was in when it molted. Bed bugs have archetypal bug characteristics, which consist of segmented bodies, antenna, and six legs. Adult bed bugs have a dark reddish-brown exoskeleton while the nymphs have light colored shells, which may appear light-brown or whitish-golden in color. Otherwise, they have the same characteristics as adult bed bugs. These bed bug skins can be found in the corner of your mattress, in the seams of your baseboard, behind the headboard, on the box springs and even stuck to your bedding or sleep-clothes. Hence you may have more chances of spotting bed bug exoskeletons than you have of seeing a live bug.

If your bed has been newly infested, there will likely be fewer bed bug casings, since the population will mostly be comprised of adults, which do not molt. However, as the outbreak increases, these adult bed bugs will breed and will give rise to immature bed bugs. Since a bed bug can lay up to five eggs each day, young nymphs will soon outnumber the adults. They will then start to molt and leave behind their skin. Since the exoskeletons do not decompose as quickly, they will build up over time and will become easier to spot.

At this stage, you already have a very large infestation.

In order for bed bugs to grow and progress to the next stage of their lifecycle, they need to feed on blood. That’s why if you do not sleep in the bed that has a bed bug infestation or protect yourself using mattress encasements, bed bug repellants, and interceptors, you can deprive these bugs of their food source in their early development stage and reduce their ability to multiply.

How Often Do Bed Bugs Shed Their Skin?

Bed bugs shed their skin soon after having a blood meal at each stage of the five nymph stages. If the food, i.e., blood, is plentiful and the temperature is optimal, each stage will last for one week under ideal conditions. However, if the temperature is cold and the food is scarce, the bed bugs will stay in their nymph stage for a longer period of time.

Once bed bugs achieve their adult stages, they are fully grown at 4.5 millimeters and will no longer shed their skin.

Some Common Places Where You Can Find Bed Bug Cast Skin

The larger the outbreak, the more bed bug cast skins you will find lying around. You will find the most amounts of bed bug shells in places where these insects like to congregate. Considering that bed bugs have the tendency to stay close to their host, you will find many casings in the seams and corners of your mattress.

Some other places where bed bug skins can be found is where the ceiling and walls meet, inside your couches and armchairs, air conditioners, your pajamas, and even your day clothes, especially, if you leave them scattered across the floor.

Does Finding Bed Bug Skins Mean You Have An Infestation?

There is a high possibility that you do have an infestation, particularly if you find more than one-bed bug skin in your home. You may think that the skin may belong to a bed bug that has died; however, remember that bed bugs shed molt five times in their lives. So, it is much more probable that you have an outbreak.

What Should You Do If You Discover Bed Bug Casings?

Don’t forget, like all pesky pests; bed bugs will only reproduce and multiply if they are not treated. If you find beg bug shells or exoskeleton on your bed, or anywhere else in your house, it is safe to assume you have an infestation. That means you need to quickly get down to business. Here is what to do:

Check Carefully

The first step is to find out where the infestation is the biggest, you can do that by turning over your mattress and inspecting its seams and box springs. If you see reddish-brown spots on your bedding, these may be bed bugs regurgitated blood, and it is a sure sign of an infestation. If you investigate closely enough, you may also find a bed bug lurking in the corners.

Getting Rid of Bed Bugs

Before calling an exterminator, you should first try to control the infestation yourself. Here are a few tips:

  • Remove your bedding and clothing and wash them in hot water. Fabric that is not suited for hot water should be subjected to your washer’s dryer after it has been laundered.
  • Use a hard-bristled brush to scrape off any bed bug skins or excrements from your mattress.
  • Vacuum your mattress to suck up as many dead bugs and eggs as you can. You should also vacuum the carpet, sofas, drapes, and walls in your home. Make sure your vacuum has a HEPA filter to ensure bed bugs do not have a chance of escaping. Throw away the vacuum bag once you are done, as it could contain eggs and live bugs.
  • Cover your mattress and pillows in thick and strong encasements.
  • Buy bed bug traps and inceptors which can prevent the pests from easily getting to you.
  • Eliminate clutter from your home and pick up clothes from the floor. These places are some of the prime hiding spots for bed bugs.
  • Use diatomaceous earth that can dry the insects from the inside out upon contact.
  • There are also many bed bug insecticides available in the market that can repel and kill bed bugs

Bed bugs are extremely resilient insects and cannot be easily killed. If you feel that your efforts are in vain, don’t be depressed. Call a professional exterminator, and they can do the job for you.

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