By Dial A Vet Veterinary Team
The fleas you see on your cat are only a small part of the problem. Most of a flea population lives in your home as eggs, larvae and pupae hidden in carpet, bedding and couch cushions, which is why fleas so often seem to come back weeks after treatment. For most cats fleas mean itching and irritation, but a heavy infestation can cause dangerous anaemia in kittens. One mistake causes serious harm every year: using a dog flea product containing permethrin on a cat, which can be fatal.
Key takeaways
- Never use dog flea products on cats. Permethrin, found in some dog products, is highly toxic to cats.
- Treat every cat and dog in the household at the same time, with species-appropriate products.
- Most of the flea life cycle happens in the environment, so cleaning the home matters as much as treating the cat.
- It commonly takes about three months of consistent treatment to break the cycle.
- Fleas spread the flea tapeworm and can trigger flea allergy dermatitis.
How the cat flea lives
The cat flea, Ctenocephalides felis, is also the most common flea on Australian dogs. Adult fleas jump onto a host, feed on blood and begin laying eggs within a day or two. The eggs fall off into the environment and hatch into larvae, which hide deep in carpets and bedding, then spin cocoons. Pupae can wait for weeks or months until warmth, vibration or carbon dioxide tells them a host is near. In warm, humid parts of Australia fleas are a year-round issue. Our page on the flea life cycle explains each stage.
Signs your cat has fleas
- Scratching, biting or overgrooming, especially around the neck, back and base of the tail
- Small scabs along the back and neck (miliary dermatitis)
- Hair loss or thinning, sometimes symmetrical on the belly or flanks
- Flea dirt: black specks in the coat that turn reddish-brown on damp white paper
- Live fleas moving through the fur
- Rice-like tapeworm segments around the bottom
- Pale gums and weakness in kittens with heavy infestations
Cats are excellent groomers and may swallow most fleas, so owners often see the itching and scabs without ever spotting a flea. Some cats are allergic to flea saliva. Read more in flea allergy dermatitis in cats.
When to see a vet
Emergency now: a cat that has had a dog flea product applied and is twitching, trembling, drooling, wobbly or having seizures. Also a kitten that is weak, cold, or has pale or white gums.
Same day: a cat with open sores, signs of skin infection, or a kitten with a heavy flea burden.
Book a visit: ongoing itching despite flea treatment, hair loss, or if you are unsure which product is safe for your cat.
What to do if you find fleas
Treat the cat
Choose a product registered for cats and suitable for your cat's age and weight. Options include spot-ons, tablets and chews, and some combination products also cover worms and other parasites. Follow the label carefully. Kittens, pregnant or nursing cats and unwell cats need vet advice first.
Treat every pet
Dogs, other cats and rabbits in the home all need treating at the same time with products made for their species. Use only cat products on cats and keep cats away from treated dogs until any spot-on has dried, as recommended on the dog product's label.
Treat the home
- Vacuum carpets, rugs, furniture and car seats every day or two for several weeks, then empty the vacuum into a sealed bag in the outside bin.
- Wash pet bedding and throws in hot water each week.
- Pay attention to dark, protected spots such as under furniture.
- Ask your vet whether a household flea spray is appropriate, and keep pets out until it is dry.
Stay consistent
New fleas may keep appearing for weeks as pupae hatch. This does not usually mean the product has failed. Keep treating every pet on schedule for at least three months.
What not to do
- Do not use any dog flea product on a cat.
- Do not use essential oils, including tea tree oil, which is toxic to cats.
- Do not use garlic or home remedies, which are ineffective and can be harmful.
- Do not combine multiple flea products without vet advice.
How vets help
Vets confirm fleas by finding fleas or flea dirt, check the skin for infection and allergy, look for tapeworm, and assess kittens for anaemia. They can recommend a product that fits your cat's age, health, lifestyle and household, and treat secondary skin infections or allergic itch if present.
Prevention
- Use year-round flea prevention on all pets, especially in warmer climates.
- Keep up regular vacuuming and bedding washes.
- Include tapeworm treatment in your cat's parasite plan if fleas have been present.
- Check new pets for fleas before they join the household.
FAQ
My cat never goes outside. How did it get fleas?
Fleas can hitch a ride indoors on people, dogs or visiting animals, and pupae can survive for months in an empty house.
Can I catch fleas from my cat?
Cat fleas bite people, usually around the ankles, but do not live on humans long term.
Why is my cat still scratching after treatment?
Itch can continue while skin heals, new fleas may still be hatching, or there may be another cause such as allergy. Speak to your vet if it continues.
Is it safe to treat a kitten?
Some products are registered for young kittens. Check with your vet and follow the label for age and weight.
Talk with a vet
A Dial A Vet consult can help you choose a safe flea plan for your cat and household. A cat that is trembling or having seizures after a flea product is an emergency, so go to an in-person emergency vet straight away.
References
- Cornell Feline Health Center: Fleas
- Companion Animal Parasite Council (CAPC): Fleas
- International Cat Care: Permethrin poisoning in cats
- RSPCA Australia Knowledgebase: Fleas on cats and dogs
Disclaimer: Educational only. This page does not replace an examination or advice from your own veterinarian. Always follow the label and your vet's advice when using parasite products.
