What serious health problems can untreated fleas cause in cats?
Updated On September 23rd, 2025
Pet's info: Cat | Mixed Breed | Male | neutered | 20 lbs
What problems can fleas cause in cats if left untreated?
3 Answers
Most Helpful Answer
Published on June 7th, 2017
While fleas may simply seem like a nuisance, the reality is that they can pose serious problems. Heavy flea infestations, particularly in very small animals, can result in significant blood loss, which causes potentially lethal anemia. Fleas can also transmit a variety of diseases, including cat scratch disease (*Bartonella henselae*) and tapeworms (*Dipylidium caninum*). Many pets are allergic to the saliva injected during a flea’s bite, and can develop severe itching, hair loss and skin infections. Fortunately, most cases of fleas can be both treated and prevented at home with the consistent use of good-quality flea preventative medications. It’s important to remember to use a flea preventative that is labeled and safe for cats. Some flea preventives for dogs are not safe for cats. Some examples of over-the-counter products that are labeled for cats include Cheristin for Cats, Capstar for Cats, Advantage II, and Frontline Plus for cats. Other products such as Comfortis for Cats, AdvantageMulti for cats and Revolution for cats are available with a prescription from your veterinarian. However, more severely affected cats require evaluation and treatment by a veterinarian. If left untreated, flea infestations in cats can also impact human health with the possibility of spreading cat scratch disease, plague or typhus. Ultimately, it is best to avoid fleas altogether with the regular use of a good quality flea preventative medication. ### Cheristin is a trademark of Elanco or its affiliates.
154Pet Parents found this answer helpful
Related Answers from Veterinarians
-
Published on September 24th, 2019
It really depends... some over the counter flea medications can cause allergic reactions. This could be what is going on. I personally never recommend using anything you can buy at the store/Petsmart/etc for cats because most of it contains pyrethrin which is an actual insecticide. It can be highly toxic. I always recommend getting flea control from your vet for two reasons: 1. You know its safe. Manufactures guarantee their products when they are purchased at a Vet. They don't when they are purchased elsewhere. 2. You can get better options. Your vet will carry things like Revolution, which not only protects against fleas, but also ear mites, intestinal worms and heartworms, which can be fatal to cats! If this issue persists, or gets worse, please go see your vet right away. If you are concerned that the product you used may have harmed your cat, give him a bath with Dawn dish soap. Good luck and feel free to consult with me privately if you have any follow up questions or concerns!
1Pet Parents found this answer helpful
-
Published on November 8th, 2017
Hi and thanks for using Petco Pet Education Center, formerly Petcoach! Great question. Enough fleas on a kitten combined with intestinal hookworms which suck blood can definitely cause great harm to a kitten including death from anemia (low red blood cell count). Fleas suck blood to reproduce and in addition, if hookworms are present, a kitten can develop a life-threatening anemia due to blood loss. Fleas can also be a source of devastating bacterial infections which can cause zoonotic disease in humans and in cats. It is always highly advised that you keep an effective flea and/or tick medicine on your cat to prevent flea infestations from taking hold on your cat and thus in your environment. Good luck and remember to consult with your veterinarian to discuss adequate external parasite control in your geographic location
1Pet Parents found this answer helpful
Can fleas kill cats?
My cat has lots of fleas and I can't get rid of them, they're even jumping on me! I give bathes once a week and get 20-30 fleas off every time
My cat is not eating kibble(he eats little wet food), lethargic, experiencing fever and has dark solid stool. Took him to the vet. Besides medicine, he was given something for his appetite and fleas. The vet mentioned about blood/circulation and flea
Hello my cats have fleas and its anoying, they been like that for years and my mom do nothing about it
I have two dogs that go outside. They are treated by a vet and have no fleas. My 2 cats already had fleas, which I have treated for many months with Advantage II. Did not help cats. One of my cats has flaking skin and sores and the other is not as ba
My cat sky has really bad fleas, she scratches herself so much she has sores on her neck. She is losing some hair from all the scratching but I've taken her to the doctor. They gave me medicine but it never fully gets rid of the fleas and some fall o
Hi there. I need to consult about 3 stray kittens we have recently fostered. I just spotted some fleas (small dark brown) running in her furr. Please help
What's best for fleas on cats?
Is it possible that our cat developed severe anemia via use of flea & tick OTC treatments? Immediately after use he showed signs/symptoms. He was 14 but healthy and active prior.
My 8+ year old indoor-only cat has been showing some signs of a pretty severe flea infestation. She’s got rough, scabby-feeling places on her skin that just look like chunks of dirt. She’s been wearing a flea collar since Saturday and has had two bat
Book an appointment with the pros – our expert vets are here to help.
