Everything you need to know about cat fleas

Share on

Cats can pick up fleas surprisingly easily and these tiny parasites can quickly spread around your home unless you act quickly to prevent an infestation. By treating your pet regularly, you will hopefully never have to deal with pesky cat fleas, but it’s still important to know the facts and what you’re up against.

Introducing the cat flea

There are more than 2,000 different species of flea in the world but the cat flea, known as Ctenocephalides felis, is the most common flea found on our pets, affecting both cats and dogs.

Cat fleas, tiny wingless insects that live on your pet’s body and feed on their blood, are the most abundant and widespread type of flea found across the world.1 Cat fleas love warm and humid environments, breeding rapidly in late summer during their peak season. However, because of modern central heating, fleas on cats (and dogs) can survive and thrive even in winter. This means you’ll need to de-flea your pets throughout the year!

Do all cats get fleas?

Both outdoor and indoor cats can get fleas. Indoor cats are at risk of getting fleas from other household pets or from you, as fleas can hitch a ride into your home on your clothing. While outdoor cats may encounter fleas on a reasonably regular basis, there are many ways for fleas to get to indoor cats too. Fleas are expert hitchhikers and can easily be carried into the home on humans, animals (such as other pets or rodents), clothing and bags.

The cat flea life cycle

A single female cat flea can lay up to 2,000 eggs in its lifetime, and its full life cycle – from egg, to larvae, to pupae, to adult – can take place in a matter of weeks. It starts when a flea jumps on your cat and feeds. They then reproduce and lay their eggs in your cat’s fur which drop off into your home.

The eggs quickly hatch into flea larvae and then transform into pupae and finally, into an adult flea. As soon as a flea emerges from its pupae, it must find a host to feed on. Fleas can only last a few days without a host and after their first blood meal they need daily blood to survive. Most fleas live for two to three weeks before being groomed out by their host, but the maximum recorded life of a flea is 160 days.

Can cat fleas live on dogs?

Although cat fleas and dog fleas are two different species, they both feed on both dogs and cats. In fact, the most common type of flea found on dogs is actually the cat flea.. This means they will quite happily jump onto other pets in the household

Should you worry about cat flea bites?

Cat flea bites are painful and itchy, and they can cause a range of additional problems:

  • Anaemia - Kittens and elderly cats are at risk of becoming anaemic from blood loss if bitten too many times.
  • Flea Allergic Dermatitis (FAD) - This is a very common allergy to flea saliva  that can set off a severe reaction in your pet from even just a few flea bites. Your cat’s skin may look sore and crusty, and they may lose fur from over-grooming, and risk exposure to infection.
  • Tapeworms - If fleas infected with the tapeworm parasite are swallowed while grooming, your cat could end up with a tapeworm infection as well as a flea infestation.
  • Bartonella (cat scratch disease) - Fleas in cats can spread disease, including a bacterium called Bartonella known as ‘cat scratch disease’. This affects cats and people, leading to fever, headaches and fatigue.
  • Typhus - Fleas can also cause a serious human disease called typhus, but this is rare.  While cases are reported worldwide, these are mainly in tropical and coastal areas.

Signs of a flea infestation in cats

In many cases it may not be obvious that your pet has fleas, as they burrow deep down into your pet’s fur and aren’t always easily visible. You should familiarise yourself with signs your pet may have fleas, which can include:

  • Scratching - You may notice that your cat is scratching more than normal.
  • Overgrooming - Overzealous or prolonged licking, biting and chewing that can lead to bald patches, sparse and damaged fur.
  • Sore skin - Scabs and red, sore areas on your cat’s skin due to scratching and overgrooming could indicate they have an allergy to flea bites.
  • Flea comb test - You can check your cat regularly by combing them gently with a flea comb. Shake the fur onto a damp piece of white tissue so you can more easily see any flea faeces (known as flea dirt) and fleas that may be hiding.

Fleas are about 1-2mm long and can be seen with the naked eye. They appear black, dark brown or reddish brown and have thin flat bodies. If you notice dark round specks on your pet’s fur or skin which look a bit like ground black pepper, this could be ‘flea dirt’ and may indicate your pet has fleas.

Flea dirt is the faecal matter of fleas and consists of undigested blood. You may also spot it around the house where your pet likes to play or rest.

Cat flea treatments

If you spot signs of fleas, don’t worry there are plenty of options to get rid of these unwanted visitors and protect your pet. Your vet will be able to advise you on the best one for your cat. Different treatments include:

  • Spot-ons - Many pet owners find spot-on treatments the simplest way to kill and prevent fleas on pets. Treatments, like Advantage spot-on, are applied to the base of your cat’s neck, from where it spreads throughout the skin, killing fleas through contact. Suitable for pets from eight weeks, Advantage kills fleas within 24 hours and is effective for up to four weeks.
  • Collars - New innovative flea collars, such as Seresto Flea and Tick Control collar can provide long-lasting protection. Seresto flea and tick control collar protects your dog or cat for up to eight months in a single application. It kills fleas and repels and kills ticks without the need for them to bite your pet.2 Whatever collar you choose, make sure it has a quick-release mechanism, otherwise your cat could get tangled while roaming the neighbourhood.
  • Sprays -  Flea sprays for your pet can be useful for kittens too small for spot-ons.
  • Tablets - Tablets are an effective treatment but because they work in the blood fleas need to bite in order for them to work, which may not be suitable for all cats. Some owners may also find it difficult to give their cat tablets.
  • Injections - While these don’t actually kill adult fleas, injections work by breaking the life cycle of a flea by preventing the development of flea eggs. One injection can last up to six months, but it has to be administered by a vet. 

Find out more about preventing and treating cat fleas.

Warning: You should never use a dog flea product on your cat as certain active ingredients used in these products can be extremely toxic to cats. If you have dogs as well as cats, speak to your vet about your options.

Don’t forget about worms

Fleas can carry the tapeworm parasite, a nasty intestinal worm which can be transmitted to your cat if ingested. It’s recommended cats are wormed at least every three months alongside flea control for full coverage. Speak to your vet about treatment options.

Getting rid of cat fleas in the home

Fleas can easily infest the home, laying eggs in the carpet and other soft furnishings. When you notice fleas have invaded, you should always treat your home as well as your cat. Remember to:

  • Wash your cat’s bedding on a hot wash
  • Vacuum the whole house, including their favourite snoozing spots, carpets, rugs, soft furnishings and even your car
  • Wash your own bedding too, especially if your cat sleeps on your bed!
  • Use a veterinary-approved household flea spray thoroughly on your home, including on sofas, curtains, and under beds. Usually these products advise you to vacuum first to bring fleas and their eggs to the surface where the spray can more easily reach them. Make sure you immediately empty the vacuum cleaner when you’re done.
  • Use a regular flea treatment on your cat to prevent reinfestation!

Read more tips on removing fleas in the home

Can humans be bitten by cat fleas?

Yes! Although cat fleas don’t live in human hair, they can bite humans, especially on the ankles and lower legs. Find out more about the risk fleas pose to humans.

Did you know...?

Fleas can produce up to 2,000 eggs in their lifetime. So, if your cat has 50 fleas, that could mean up to 100,000 eggs falling into your home waiting to hatch!


1 Lance A. Durden, Nancy C. Hinkle, Fleas (Siphonaptera) in Medical and Veterinary Entomology (Third Edition), 2019

2 Information is regarding mode of action and is not intended to imply parasites can be completely stopped from biting; an attachment of single ticks after treatment cannot be excluded

Use Medicines Responsibly.

Seresto Flea and Tick Control  collar contains imidacloprid and flumethrin [NFA-VPS]. Further information is available from the datasheet at www.noahcompendium.co.uk or on request. The Bayer cross is a Registered trademark of Bayer AG. Seresto, Elanco and the diagonal bar logo are trademarks of Elanco or its affiliates. Elanco UK AH Ltd., Form 2, Bartley Wood Business Park, Bartley Way, Hook, RG27 9XA. Tel. 01256 353131. 

Share On