The mattress seam is where this is settled. Five minutes with a torch tells you more than a fortnight of wondering about bites.
Dark spots on the mattress seam or piping — digested blood, like a fine felt-tip mark that does not brush off. That is the most reliable sign there is.
Then live insects, shed skins and small blood smears on the sheet. Bites are the least reliable evidence, because reactions vary enormously.
Five minutes, properly done, settles it either way.
| Sign | What you are looking at |
|---|---|
| Dark spots | Digested blood. Fine felt-tip marks on the seam that do not brush off |
| Live bug | Flat, oval, reddish-brown, 4–5mm. Rounder and darker after feeding |
| Shed skins | Pale translucent insect shapes; they moult five times |
| Eggs | About 1mm, pearly white, cemented into a crevice — hard to see |
| Blood smears | Small rust marks on the sheet where one was crushed |
| Smell | Sweetish, musty — only in a heavier case |
See our full bed bug treatment service, published room prices and preparation guidance.
View Bed Bug Control Pinner →If the mattress is clear and you are still being bitten, keep going.
If a bite reaction is severe, spreading or infected, that is a matter for a doctor. What it is not is a way of confirming what bit you.
| What you are seeing | Possibly |
|---|---|
| Bites mainly on ankles and lower legs, and there is a pet | Fleas |
| Itchy rash, no bites found, bristly larvae in the carpet | Carpet beetle larval hairs |
| Bites only outdoors or at dusk | Mosquitoes or midges |
| Itching with no marks at all | Dry skin, fabric, detergent — a doctor's question |
| Bites in a line, plus dark spots on the mattress seam | Bed bugs |
Yes, early on. That is why the dark spots on the seam matter more than the insects.
Mostly, but a heavy infestation will feed in daylight.
Yes, particularly one that gets slept on — and particularly an older upholstered one.
Stung outdoors instead? A wasp nest is £90 fixed cost in Pinner, guaranteed for 30 days.
Dark spots on the mattress seam or piping — digested blood, like fine felt-tip marks that do not brush off.
Strip the bed, take a proper torch, start at the seam and piping all the way round both sides, and run a card along the seam. Then the base, frame joints and headboard.
Flat, oval, reddish-brown and about 4–5mm — apple-pip sized. Rounder and darker after feeding.
Frame joints and screw holes, the headboard, under-bed drawers, skirting joints — and in a period room, the gap behind the skirting and the architraves.
No. Reactions vary enormously, some people show nothing, and no doctor can diagnose bed bugs from a bite.
In a home with a pet, very possibly — flea bites are typically on the ankles and lower legs.
Take a torch and look at joints, screw holes, upholstery seams, the underside and inside drawers. It takes two minutes.
Photograph it, do not strip everything, do not move rooms, do not throw the bed out, and do not spray it.
Photograph the mattress seam and send it. That usually settles it before anyone visits.
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