The short answer
An adult bed bug is flat, oval and reddish brown, about 5 mm long, roughly the size and shape of an apple pip. After feeding it swells and turns darker and redder. Young bugs are smaller and paler, almost see-through until they feed, and the eggs are white, about 1 mm long, and usually stuck in seams and cracks near the bed.
Most people who search this have just found something small and brown on the sheet, or have woken up with a row of itchy bites and want to know what to look for. Bed bugs change in looks as they grow and as they feed, which is why a single photo online can be misleading. Here is what each stage looks like, what they leave behind, and how to be sure.
Adult bed bugs
A grown bed bug is about 5 mm long, which the NHS compares to the size of an apple pip. That comparison is a good one: it is a similar shape too, a flattened oval, broader at the back than the front.
Colour and shape before and after feeding
An adult that has not fed for a while is a flat, rusty brown and thin enough to slide into a crack the width of a credit card. After a feed it changes a lot. The body swells, becomes longer and rounder, and turns a darker, redder brown. A recently fed bug can look almost like a tiny red bean.
Other details you can see
Up close, or with a phone camera zoomed in, you can see six legs, two short antennae at the front, and fine bands across the back of the body. Bed bugs have no working wings, so they cannot fly, and they do not jump. They crawl, and faster than most people expect.
Young bed bugs (nymphs)
Bed bugs hatch as miniature versions of the adult and grow through five stages, shedding their skin each time. The youngest are around 1 mm long, about the size of a pinhead.
Before they feed, young bed bugs are pale, a creamy or straw colour, and so thin they can be almost see-through. Straight after a feed they show a bright red spot of blood inside the body, which is often the only reason anyone notices them. As they grow they darken towards the adult colour.
Bed bug eggs
The eggs are white or pearly, about 1 mm long and shaped like a grain of rice. They are stuck down with a kind of glue, so they do not brush off easily. You will usually find them in tight places close to where people sleep: along the seams and piping of a mattress, in the joints of a bed frame, behind a headboard or along the edge of a skirting board.
Once an egg hatches it leaves a clear, empty shell behind. Clusters of these empty shells, together with the pale skins young bugs shed as they grow, are some of the clearest signs of an established problem.
The marks they leave
Often you find the evidence before the bugs themselves. Three things are worth knowing.
- Dark spots. Bed bug droppings are digested blood. They look like small black or dark brown dots, as if someone has dabbed the fabric with a felt-tip pen, and they tend to bleed into the fabric rather than sit on top.
- Small blood stains. Rusty smears on sheets or pillowcases, often from a bug being squashed after feeding.
- Shed skins. Pale, papery husks in the shape of a bug, left in seams and cracks.
What else could it be?
A few common household insects get mistaken for bed bugs. Carpet beetles are rounder and often patterned, and their larvae are hairy. Booklice are much smaller, pale and soft, and live in damp places rather than beds. Fleas look squashed sideways, like a coin on its edge, and they leap when disturbed. Spider beetles are round and shiny, more like a tiny bead with legs. If you are in any doubt, keep the insect and ask a technician to identify it.
Where to look in your home
Bed bugs feed on people, usually at night, and then hide nearby, so the search starts at the bed. Strip the sheets and use a torch on the mattress seams, labels and corners, the base or divan, and the frame. Then work outwards: the headboard, bedside tables, plug sockets near the bed, the skirting board, and any sofa that someone sleeps on.
In a Newcastle Tyneside flat, it is also worth asking your neighbours. The upper flat’s bedrooms are often above the lower flat’s, so if one household finds bed bugs the other should look too. Our inspection page explains what a professional search covers.
If you think you have found one
Do not squash it if you can avoid it. Trap it in a zip-lock bag or a clean jar with a lid, ready for a technician to name. Then:
- Keep sleeping in your usual bed. Moving to the sofa tends to spread the problem.
- Wash bedding and clothes from that room on a hot wash and tumble dry them, as the NHS suggests, then keep them in sealed bags.
- Do not throw out the mattress yet. Carrying it through the house can drop bugs and eggs on the way.
- Get it confirmed. A technician can identify a bug in seconds and tell you how far it has spread.
If you rent from Newcastle City Council, report it to your housing office first. Owners and private renters will usually need a private firm, and our price guide shows typical costs.
If you have found something and want a technician to look at it, send us your postcode. We look for a local firm that covers your area and tell you who they are before passing anything on.