Identifying fleas

What a flea looks like

A flea is tiny, usually 1 to 3 mm long, dark reddish-brown and wingless. Its body is flattened from side to side, which lets it move through fur and carpet fibres. You may see one jump, but fleas move too quickly to catch and inspect easily.

Larvae and eggs are even harder to spot, and live in carpets, bedding and floor gaps rather than on you.

Flea bites on people

The NHS describes flea bites as groups of large red raised bumps below the knees. They often appear in twos or threes on the ankles and lower legs. They itch, and scratching can make them sore.

The pattern matters. Bites on the ankles and legs fit fleas. Bites on exposed skin of the face, neck and arms, found after a night in bed, fit bed bugs. For the NHS advice on bites and stings, see the NHS guide.

Where to check in the home

Fleas and their eggs gather where pets rest and where people walk. Check pet beds, rugs, the edges of fitted carpets, sofas and the gaps along skirting boards. Press a sheet of white paper or a pale sock against the floor and look for dark specks or small jumping insects. Do this in the morning, before you vacuum.

If you find flea dirt in more than one room, the problem has spread beyond the pet's bed. At that point a whole-home treatment makes more sense than spot cleaning.

The flea dirt test

Flea dirt is digested blood, and it shows as tiny dark specks on pet bedding, rugs and carpets. To test it, put a few specks on damp white paper or a damp tissue. If they smear red or reddish-brown, it is flea dirt.

A scratching pet is another clue. Ask your vet to check the animal. This guide covers the home only.

Lookalikes

Three things are often mistaken for fleas:

• Bed bugs bite exposed skin on the face, neck and arms in bed.
• Bird or bat mites bite after a nest nearby, such as in a loft or under eaves.
• Carpet beetle larvae are another lookalike that can cause skin reactions.

A technician should name the species before spraying, because the treatments differ. Photograph what you find and share it with the firm.

What to do once you are sure

If you have confirmed fleas, treat the home and the pet together. Ask your vet about the pet. For the home, vacuum daily and wash soft furnishings hot, and call a pest controller if bites carry on for two to three weeks. If you cannot confirm fleas, or the bites do not fit the pattern, ask a technician to identify the insect before anything is sprayed.

When fleas show up

Fleas thrive in warm, humid weather and in heated homes, and reports tend to climb from late summer into autumn. Pupae can lie dormant for weeks, months or up to a year, so an outbreak can appear when you move in or return from holiday to an empty home.

Once you are sure they are fleas, our flea treatment page explains what a professional does, and the DIY guide covers what you can try first.