Is It a Bed Bug? How to Tell Bed Bugs From Look-Alikes
Bed Bugs: 4 marks to check, what they are often confused with, whether they bite or sting, and where they turn up, quoted from university entomology and IPM sources.
At a glance
- Group: Bed bugs are insects of the order Hemiptera; the common species is the common bed bug, Cimex lectularius.
- Body plan: Bed bugs have a flat, oval body; both adults and nymphs are wingless, with long, slender legs and antennae; mouthparts are a tube-like piercing stylet used for feeding on blood; adults are about 1/4 inch long and reddish-brown.
- Size: Adults are about 1/4 inch (about 6 mm) long; nymphs are smaller than adults.
- Bites or stings: Bed bugs feed on blood; bites are usually painless and hard to notice during sleep. Anticoagulant and anesthetic compounds in their saliva typically cause an allergic reaction — a colorless welt or bump at the bite site that turns red and itchy only days later — though some people have no reaction at all. The source explicitly states bed bugs do not transmit disease.
- Where you find them: Mainly hide in bedrooms: mattress seams and tufts, inside box springs, bed frame joints, behind headboards/footboards, under loose wallpaper — crevices close to the sleeping area.
How to tell it is one of the bed bugs
- Bed bugs are flattened top-to-bottom and oval, and adults are wingless for life, only able to crawl and not jump — clearly different from fleas, which are laterally flattened with hind legs specialized for jumping.
- Bed bugs are smaller, more rounded, and wingless as adults, distinguishing them from the larger but similar-looking kissing bug (conenose bug).
- Bed bugs hide by day in concealed spots such as mattress seams, bed frame joints, and behind loose wallpaper, coming out at night to feed on blood — you need to check these hiding places rather than only looking at the person's body.
- Bed bug bites are usually painless and go unnoticed during sleep, with redness and itching appearing only days later; but distinguishing the bite itself from mosquito, flea, or spider bites is difficult to impossible.
Often confused with
People most often mix bed bugs up with:
Open the other page and compare its list against the marks above; the differences are usually in the antennae, wings or the way the body is divided.
Bites and stings
Bed bugs feed on blood; bites are usually painless and hard to notice during sleep. Anticoagulant and anesthetic compounds in their saliva typically cause an allergic reaction — a colorless welt or bump at the bite site that turns red and itchy only days later — though some people have no reaction at all. The source explicitly states bed bugs do not transmit disease. Seek medical care promptly for severe symptoms or any allergic reaction.
Where they turn up
Mainly hide in bedrooms: mattress seams and tufts, inside box springs, bed frame joints, behind headboards/footboards, under loose wallpaper — crevices close to the sleeping area.
How to photograph it for identification
Get as close as your camera will focus, from directly above, in daylight or a bright lamp. Include the whole body with the legs and antennae in frame; a second shot from the side shows wings and body segments. Put a coin or ruler next to it for scale. For a bite or a bug found on skin or bedding, photograph the bug itself, not the mark. The app names the likely group; use the list above to confirm.
FAQ
Do bed bugs bite or sting?
Bed bugs feed on blood; bites are usually painless and hard to notice during sleep. Anticoagulant and anesthetic compounds in their saliva typically cause an allergic reaction — a colorless welt or bump at the bite site that turns red and itchy only days later — though some people have no reaction at all. The source explicitly states bed bugs do not transmit disease. Seek medical care promptly for severe symptoms or any sign of an allergic reaction.
What is the quickest way to recognize bed bugs?
Bed bugs are flattened top-to-bottom and oval, and adults are wingless for life, only able to crawl and not jump — clearly different from fleas, which are laterally flattened with hind legs specialized for jumping.
How do I tell bed bugs from fleas?
Bed bugs are flattened top-to-bottom and oval, and adults are wingless for life, only able to crawl and not jump — clearly different from fleas, which are laterally flattened with hind legs specialized for jumping. Bed bugs hide by day in concealed spots such as mattress seams, bed frame joints, and behind loose wallpaper, coming out at night to feed on blood — you need to check these hiding places rather than only looking at the person's body. The Fleas page lists its own marks.
Related
See what's really crawling, flying, and buzzing past.
Start with a single photo.
Sources
- https://extension.psu.edu/biology-habitat-and-management-of-bed-bugs
- https://ipm.ucanr.edu/home-and-landscape/bed-bugs/
Updated 2026-09-11.