What Do Bed Bugs Look Like?
Adult bed bugs are small — about the size of an apple seed, roughly 5–7mm long. They are flat, oval-shaped, and reddish-brown when unfed. After feeding, they become engorged, darker, and balloon-shaped. They do not fly and do not jump.
Key physical features:
- Flat, oval body (unfed) or swollen and elongated (fed)
- Six legs, two antennae
- Reddish-brown to mahogany coloring
- Distinct banded abdomen with segmentation visible
Bed bugs are often confused with bat bugs, swallow bugs, and carpet beetles. The key distinction: bed bugs have a distinctly round head and thorax much narrower than the abdomen, with short golden body hairs.
Bed Bug Eggs and Nymphs
Eggs are tiny — about 1mm, pearl-white, and shaped like a grain of rice. A female bed bug lays 1–5 eggs per day and up to 500 over her lifetime. Eggs are sticky and found in clusters in crevices, often along mattress seams, behind headboards, or in furniture joints.
Nymphs (baby bed bugs) go through five molting stages before becoming adults. First-stage nymphs are nearly transparent and about 1.5mm — barely visible to the naked eye. They darken through each instar. All nymphs require a blood meal to molt to the next stage.
Finding shed skins (exuviae) is a strong indicator of an active infestation. Each bed bug sheds 5 skins over its development — a cluster of shed skins signals a population that has been there for at least several weeks.
Signs of Bed Bugs: What to Look For
You may have bed bugs without ever seeing a live insect. The signs they leave behind are often easier to spot:
- Rusty-red stains: Crushed bed bugs leave blood smears on sheets and mattress surfaces
- Dark fecal spots: Digested blood excrement appears as dark brown or black dots — roughly the size of a marker tip — on mattress seams, walls, headboards, and outlet covers
- Shed skins: Pale yellowish molted exoskeletons in harborage areas
- Eggs and egg casings: Small white oval shapes, often in tight crevices
- Live bugs: Check mattress seams, box spring folds, bed frame joints, and behind headboards with a flashlight
The characteristic musty, sweet odor often described with heavy infestations comes from the bugs' scent glands — but by the time you can smell it, the infestation is typically significant.
Where to Inspect First
Bed bugs harbor close to their food source. In a bedroom, inspect in this order:
- Mattress seams, tufts, and folds
- Box spring (remove the dust cover if present)
- Bed frame joints, screw holes, and slats
- Headboard — especially if wall-mounted (remove and inspect the back)
- Nightstands: drawers, joints, undersides
- Electrical outlets on walls adjacent to the bed
- Baseboards and carpet edges near the bed
- Upholstered furniture — seams, cushion edges, undersides
In severe infestations, bed bugs disperse further — behind wall plates, inside electronics, inside curtain folds, and even behind picture frames. If you find signs in multiple rooms, the infestation has had time to spread.
When to Call a Professional
If you find any combination of live bugs, eggs, shed skins, and fecal spotting, professional treatment is the appropriate next step. DIY methods — sprays, foggers, and powders — have poor efficacy against established infestations and can scatter bugs deeper into walls and adjacent units.
A professional K-9 bed bug inspection is the most accurate detection method available, with trained dogs capable of detecting infestations at the egg stage with greater than 95% accuracy when properly certified. This is especially important in multi-unit buildings where adjacent unit inspection determines the true scope of the problem.