Signs of Bed Bugs: How to Tell If You Have Them

You woke up with a few itchy bumps on your arm. Maybe it is a mosquito. Maybe it is a skin reaction. But part of you is wondering whether it is something worse. The anxiety that comes with even suspecting bed bugs is real, and it is made worse by the fact that most people do not know what to look for. A bed bug infestation can go weeks before being identified, and in that time the population grows.

The good news: bed bugs leave evidence. If they are present, you can find proof without hiring an exterminator for the initial check. Here is exactly what to look for and where to look.

Sign 1: Fecal Spots

This is often the first evidence people notice, sometimes before they ever see a live bug. Bed bug fecal spots are small (1-2mm), dark brown or black dots that appear on sheets, pillowcases, and mattress seams. They look like someone touched the fabric with a fine-tip marker.

The spots are digested blood. They smear slightly when wiped with a damp cloth, which distinguishes them from dirt or fabric defects. You will typically find them in clusters along mattress seams, especially at the corners and along the piping. They also appear on pillowcases near where your head rests and on the fitted sheet in the area where your torso lies.

If you see a few isolated spots, it does not necessarily confirm bed bugs. Other insects leave similar marks. But clusters of spots along mattress seams combined with any other sign on this list makes the diagnosis more certain.

Sign 2: Shed Skins (Exoskeletons)

Bed bugs moult five times before reaching adulthood. Each moult leaves behind a translucent, light brown shell in the shape of the bug. These shed skins are the same size and shape as the bug at that stage, from nearly invisible (early nymphs, about 1mm) to apple-seed size (pre-adult, about 5mm).

Look for them along mattress seams, in the crevices of your headboard, inside the joints of your bed frame, and in the channels of nightstand drawers. Shed skins accumulate over time, so finding multiple skins of different sizes suggests an established and growing population.

Sign 3: Bites

Bed bug bites typically appear as red, raised welts that itch. They often appear in a line or cluster of three to five bites (sometimes called "breakfast, lunch, and dinner"), usually on exposed skin: arms, shoulders, neck, and face.

The complicating factor is that roughly 30% of people do not react visibly to bed bug bites. You can be bitten repeatedly without developing welts. This is why physical evidence on the mattress and bed frame matters more than bite marks alone. It is also why some infestations grow undetected for weeks in households where the occupants do not react to bites.

Conversely, bites alone do not confirm bed bugs. Mosquitoes, fleas, and even dry skin can produce similar-looking marks. Bites combined with fecal spots or shed skins is the confirmation.

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Sign 4: Musty Odour

Bed bugs release pheromones that produce a sweet, slightly musty smell. In small infestations, this may not be noticeable. In larger ones, the smell is distinct and often described as similar to coriander or slightly overripe berries. Professional bed bug detection dogs are trained to identify this scent.

If your bedroom has developed an unusual sweet or musty smell that you cannot trace to another source, and it is strongest near the bed, it is worth investigating for bed bugs.

Sign 5: Live Bugs

Adult bed bugs are about 5mm long (apple seed size), flat, oval, and reddish-brown. After feeding, they become darker and more swollen. Nymphs (juveniles) are smaller and lighter, nearly translucent when unfed.

Bed bugs are nocturnal and hide during the day. You are unlikely to see them unless you look in their hiding spots. Pull back your sheets and check the mattress seams with a flashlight. Look along the piping, at the corners, and in any tufting or seam that creates a crevice. Check the headboard, particularly behind it if it is wall-mounted, or in the joints if it is attached to the frame.

Where to Look

Bed bugs prefer to hide within 1-2 metres of where you sleep. Start close and work outward:

1. Mattress seams and piping. This is the most common hiding spot. Run your fingers along every seam, especially at the corners. Use a flashlight and a credit card to probe into the seam folds.
2. Box spring. If you have one, flip it or remove the dust cover on the bottom. Bed bugs hide in the staple points, corner protectors, and along the wooden frame inside.
3. Headboard. Behind a wall-mounted headboard. In the joints and fastener holes of a bed-frame headboard. Fabric headboards are particularly vulnerable because the material provides many hiding spots.
4. Bed frame joints. Any point where two pieces of wood or metal connect. Screw holes, bracket slots, and where slats meet the frame.
5. Nightstand. Inside the drawer, along the back panel, under the drawer slides. Bed bugs do not just live in the bed. They live near the bed.
6. Baseboards and electrical outlets. In heavier infestations, bed bugs move into wall voids, behind baseboards, and inside electrical outlet covers near the bed. If you find bugs here, the infestation has been established for some time.

What to Do If You Find Evidence

If your inspection confirms bed bugs (fecal spots + shed skins + live bugs), take these steps:

• Do not panic. Bed bugs are unpleasant but not dangerous. They do not transmit diseases. The problem is solvable.
• Do not start spraying. Over-the-counter bed bug sprays are largely ineffective against modern populations and can drive bugs deeper into walls and furniture, making professional treatment harder. Chemical resistance in bed bug populations is well documented.
• Contact a licensed pest control professional. Heat treatment (raising the room to 50°C+ for several hours) is the most effective single-treatment option. Chemical treatment requires multiple visits over 2-3 weeks. Discuss both options with your exterminator.
• Wash all bedding on hot. At least 60°C (140°F) wash and 30 minutes in a hot dryer. Heat kills bed bugs at all life stages including eggs.
• Install a mattress encasement. After treatment, a full-zippered encasement traps any surviving bugs inside the mattress and prevents recolonization. This is essential for long-term prevention. Our mattress encasements at Mattress Miracle cover all six sides with zippered closure.