The short answer
The NHS lists four main signs of bed bugs: bites on skin that is exposed in bed, small blood spots on the sheets, tiny brown or black droppings, and the bugs themselves, which are about 5mm long and yellow, red or brown. Check the seams of the mattress, the joints of the bed frame and the headboard first.
Bed bugs are good at hiding, and an early infestation can be easy to miss. Often the first clue is a few itchy bites, and people put them down to something else. Knowing the signs means you can act while the problem is small and cheaper to treat.
This guide covers what the NHS and the British Pest Control Association (BPCA) say to look for, and where.
The four main signs
1. Bites
The NHS says bed bug bites tend to appear on skin that is exposed while you sleep, such as the face, neck and arms. They are often itchy and raised, and can appear in a line or a group. Some people react strongly; others barely notice them. Bites on their own do not prove you have bed bugs, because other insects bite too, so look for the other signs as well. Our guide to bed bug bites covers what the NHS advises.
2. Blood spots on the sheets
Small spots or smears of blood on sheets and pillowcases are one of the commonest signs. They happen when a bug that has just fed is squashed as you turn over, or when a bite bleeds a little.
3. Droppings and dark stains
Bed bug droppings are tiny brown or black spots, a bit like the dot from a felt-tip pen. They often gather in clusters along mattress seams, on the bed frame and on the wall near the headboard. On fabric they can soak in and look like small dark stains. Many people searching for early bed bug stains on sheets are seeing exactly this.
4. The bugs themselves
Adult bed bugs are flat, oval and about 5mm long, roughly the size of an apple seed. The NHS describes them as yellow, red or brown. They look darker and more rounded after feeding. Young bed bugs, called nymphs, are smaller and paler and can be hard to see.
Other signs
- Shed skins. Young bed bugs shed their skin five times as they grow, according to the BPCA. The empty pale casings collect where the bugs hide.
- Eggs. Tiny, white and about 1mm long, glued into cracks and seams.
- A smell. A heavy infestation can give off a sweet, musty smell. You are unlikely to notice it early on.
Where to look
Bed bugs stay close to where people sleep or sit for long periods. The NHS lists mattresses, bed frames, furniture, the backs of pictures and loose wallpaper among their hiding places. Work through the room in this order:
- The mattress. Lift the sheets and check the seams, piping, tags and any folds, especially at the head end and the corners.
- The bed frame and headboard. Joints, screw holes, slats and the back of the headboard. Divan bases have fabric undersides worth checking with a torch.
- Bedside furniture. Drawers, the underside of tables and the joins of the frame.
- Sofas and armchairs. Seams, under cushions and the fabric underneath, particularly if someone sleeps or naps there.
- The walls. Skirting boards near the bed, behind pictures, loose wallpaper, and around plug sockets and light switches.
A torch and a thin card, such as an old bank card, help you look into seams and push out anything hiding there.
Signs in hotels and rented rooms
The NHS advises checking luggage and second-hand furniture, and when you stay away it is worth checking the bed before you unpack. Pull back the sheet at the head end and look at the mattress seams and the headboard. Keep your case on a luggage rack or a hard surface away from the bed, and check it before you bring it home. Landlords and hotels can read our page on commercial bed bug treatment.
Could it be something else?
Spots on sheets can come from many things, and itchy bites can come from fleas, mites or mosquitoes. A few points help tell them apart:
| What you find | Points to bed bugs | Points to something else |
|---|---|---|
| Bites | In lines or groups on skin exposed in bed | Around the ankles and lower legs, often with pets in the home (fleas) |
| Spots on bedding | Blood spots plus clusters of dark dots on seams | Single marks with no droppings nearby |
| Insects | Flat, oval, reddish brown, about 5mm, do not jump | Tiny and jumping (fleas) |
If you are unsure, a pest control firm can confirm it. Some use trained detection dogs for larger buildings.
What to do if you find signs
Do not move bedding or furniture to another room, as this can spread the bugs. Wash and tumble dry bedding and clothes on hot settings, as the NHS advises, and bag anything you cannot wash. Avoid shop-bought sprays: the BPCA says amateur pesticides rarely work and can drive bed bugs into other rooms.
Then get it treated. Heat treatment kills bed bugs and their eggs in one visit, and our cost calculator shows typical prices. To find a specialist who covers your area, use the form below.