Identification Guide

Bed bugs vs fleas: how to tell which one you have

Both bite. Both itch. Both can ruin a household's sleep for weeks. But bed bugs and fleas are completely different insects with different behaviour, different hiding places and (in some cases) different treatment priorities. This guide walks through every signal you can check yourself — bite patterns, what the insect looks like, what they leave on bedding and carpets, and how each spreads — so you know what you are actually dealing with before you book a treatment.
0204 569 0701Request a quote

The five-second summary

Bed bugs hide near where you sleep and bite at night. Fleas live on or near pets (or fox-frequented gardens) and bite throughout the day, mostly on ankles. If the bites are on your upper body and you wake up with new ones, think bed bugs. If your ankles are covered and the dog is scratching, think fleas.

Bite patterns

Bed bug bites

  • Exposed skin only — arms, shoulders, neck, face, hands.
  • Linear or clustered ("breakfast, lunch and dinner" pattern of three).
  • Often only appear hours later, so easy to miss the cause.
  • Not everyone reacts — one partner can be covered, the other untouched.

Flea bites

  • Ankles, calves, behind the knee.
  • Small (1–2mm) with a clearly visible central red dot (puncture).
  • Often appear in twos and threes but more scattered than bed bugs.
  • React instantly — itch within minutes, not hours.

The insect itself

Bed bugs are flat, oval, the size and shape of an apple pip, reddish to dark brown depending on when they last fed, and do not jump or fly. Crush one after a feed and it leaves a red blood smear.

Fleas are smaller (1–3mm), darker, narrow and laterally flattened (thin from side to side), and jump — often several inches — when disturbed. Catch one between damp tissue and it turns the tissue rusty red.

Where they live

  • Bed bugs: mattress seams, headboard joints, behind skirting, bed-frame screw holes, sofa seams, inside bedside drawers. Always near where humans sleep or sit for long periods.
  • Fleas: carpets, rugs, pet bedding, under sofa cushions, in cracks of wooden floors. Larvae fall off the host into the environment, which is why a carpet treatment alone often fails.

Evidence left behind

  • Bed bugs: black ink-dot faecal spots along mattress piping, pale yellow shed skins, a sweet musty smell in heavy infestations, and small blood smears on sheets.
  • Fleas: "flea dirt" — gritty black specks in pet bedding or carpet that turn rusty-red on damp white tissue. White flea eggs in carpet pile.

Why heat treatment kills both

Adults, larvae, eggs and pupae of both species die at sustained temperatures above 50°C. Our protocol takes the entire room to 55–60°C core, held for 2–3 hours. Unlike sprays, heat reaches inside mattresses, carpet pile, sofa frames and skirting voids, which is exactly where both pests hide. One visit, no chemical residue, safe to sleep in the same night.

Common scenarios across our service area

  • Returning traveller waking up with bites in a Westminster (SW1) or Camden (NW1) flat — almost always bed bugs picked up in a hotel.
  • New tenant in a Watford (WD17) or Romford (RM1) terrace with ankle bites and previous pet ownership — usually a residual flea infestation from larvae in the carpet.
  • HMO room in Tower Hamlets (E1) or Hackney (E8) with bites on multiple residents — bed bugs spreading between rooms.
  • Family home in Guildford (GU1) or Maidstone (ME14) with the dog scratching and ankle bites — fleas, often introduced by foxes in the garden.

Where we deliver this service

We respond across London and the Home Counties on the same day. Click any location below for postcode-level coverage, response times and pricing for that exact area.

See all areas we cover

Frequently asked questions

Do bed bug bites and flea bites look different?

Yes. Bed bug bites are usually on exposed skin (arms, neck, face) and appear in lines or clusters of three. Flea bites are concentrated around the ankles and lower legs, are smaller, and have a tiny red dot in the centre.

Can I see bed bugs and fleas with the naked eye?

Both are visible. Bed bugs are flat, oval, apple-pip sized and reddish-brown. Fleas are smaller (1–3mm), dark, and famously jump several inches when disturbed.

If I do not have pets, can it still be fleas?

Yes — cat fleas can be brought in on second-hand furniture, by foxes nesting under decking, or left behind by a previous tenant. But in pet-free homes, bed bugs are statistically far more likely.

Does heat treatment work for both?

Yes. Our 50–60°C whole-room heat treatment kills bed bugs, fleas, eggs and larvae in a single visit. The protocol is identical.

How do I tell from the bedding alone?

Bed bugs leave small black ink-dot faecal spots along mattress seams and behind headboards. Fleas leave 'flea dirt' — small dark specks that turn rusty-red when rubbed on damp white tissue (digested blood).

Same-day callouts across London and Home Counties?

Yes. Whether you are in Camden NW1, Watford WD17, Romford RM1, Maidstone ME14 or Guildford GU1, we can usually be on site the same day to confirm identification and treat.

Related guides

Not sure what's biting you? We'll confirm on site.

0204 569 0701

7 days a week · Same-day response · Written 6-month guarantee