How Do Indoor Cats Get Fleas?

You might think it’s impossible for an indoor-only cat to get fleas. Wrong! Here’s why.

How Do Indoor Cats Get Fleas?
Because they multiply so quickly, fleas are difficult to treat. But how do indoor cats get fleas? Photo: coyot

Many people think that because they have an indoor-only cat, fleas are impossible.

They would be wrong.

Although an outdoor cat is more likely than a strictly indoor cat to be infested with fleas (as well as ticks and intestinal worms), an indoor cat can, in fact, attract these parasites.

How Do Indoor Cats Get Fleas?

First, know this: A flea can jump more than 100 times its own length.That alone should tell you something about how sneaky fleas can be.

Anything, or anyone, can unknowingly bring a flea into your home. It’s pretty easy for a flea to jump on your clothes when you’re walking outside. The flea will simply hitch a ride on your pants, sock or shoe.2

Or maybe your dog goes outside for while, picking up a flea before coming back into the house. Fleas are so tiny, they can even enter your home on their own, jumping through screens or coming in through the smallest cracks of a door or window.3

Once inside, the flea jumps onto your cat. And that’s that, right?

Well, not quite. Let’s say that single flea is female. If so, then there’s much more to the story on how indoor cats get fleas.

Vacuum often to help prevent a flea invasion of your home — even if your cat is strictly indoor only. Photo: Esoathlete144

From a Single Flea to Hundreds

After a little feast on your poor indoor cat, that single female flea then jumps off to lay hundreds of eggs, which will quickly hatch in 1–10 days, becoming hundreds of hungry larvae.4

Vetstreet, in its Pet Owner’s Guide to Flea Control, notes that “flea larvae are mobile, and they can hide in places such as carpeting, bedding, furniture, and baseboards.”5

Unfortunately, “it only takes 21 days for a single flea to multiply into 1,000 fleas on your dog or cat and in your home,” according to information provided by Sergeant’s Pet Care Products.6

All those new fleas are then ready to satisfy their thirst with the blood of your cat. Thus begins another cycle.

“For something so small — just 1/12 to 1/8 inches long — fleas are a mighty big problem,” says Sergeant’s, adding that “one flea can bite up to 400 times per day.”

Getting Rid of Fleas Feels Like an Impossible Task

The worst thing about a flea infestation, though, is that your cat can’t get away from these pests, regardless of how much your cat grooms. Anyone who has dealt with a flea infestation knows how rapidly this problem can spread to other pets in your home.

Fleas can disrupt your cat’s happy-go-lucky lifestyle, possibly causing problems like:

  • Anemia, especially in young kittens or older cats
  • Flea allergy dermatitis
  • Tapeworms
  • Bartonella species infections
  • Mycoplasma species infections7–9

If your cat is continuously scratching or has skin problems such as sores, a flea may be partly to blame.

“If you believe your pet is infested with fleas, begin with a trip to your veterinarian,” advises Vetstreet. “Your pet may have a skin infection or other problem that needs attention.”

Treating an Indoor Cat With Fleas

Instead of running out and buying the first flea shampoo you see on the shelf, see your vet, who can recommend the most effective, safest treatment.

“Talk with your veterinarian,” says Dr. Debora Lichtenberg, VMD, a veterinary writer for Petful. “Buy products wherever you like — but get intelligent advice first.

“If your flea problem is truly out of control and you have an infestation, you may need to treat your home,” she suggests.

Don’t miss Dr. Lichtenberg’s related article, “The Best Way to Treat Fleas — From a Veterinarian.”

Preventing Fleas on an Indoor Cat

Check your cat daily for fleas.

Even if you don’t actually see any, you may notice a few telltale signs they are present: Their eggs and excrement (“flea dirt”) will resemble reddish-black pepper or flecks on the fur.

“Comb the pet with a flea comb and place the collected debris on a piece of white paper towel moistened with water,” advises Dr. Charles Hendrix, DVM.10

“Rubbing the flea dirt with a fingertip causes the flea dirt to dissolve, producing a characteristic blood-red or rust-red color,” he says. That’s how you’ll know your indoor cat has fleas.

One way of preventing a flea infestation in your home is to vacuum your carpets often to suck up any stray fleas. Be sure to empty the vacuum cleaner bag/canister after each use — fleas can reproduce inside the bag and escape, ready to strike again.

If your indoor cat goes outside occasionally, you may find a spot-on monthly preventive or an oral medication to be quite effective.

These preventives often control ticks as well, so don’t hesitate to ask your vet about these options to keep your indoor cat flea-free.

Listen to this vet talk about threats to indoor cats:

YouTube player


  1. Berenbaum, May, PhD. “Flea-Flickers and Football Fields.” American Entomologist. Fall 2008. 132.
  2. “Pests of Homes, Structures, People, and Pets: Fleas.” University of California Statewide Integrated Pest Man­agement Program. September 2010.
  3. Paredes, Glenda, DVM, and Garey Smith. How Healthy Is Your Pet?: A Guide to Understanding Your Pet’s Healthcare. BookBaby. 2018.
  4. Billings, Sharon, CVT. “The Ubiquitous Flea!” Pet Poison Helpline.
  5. “A Pet Owner’s Guide to Flea Control.” Vetstreet. March 7, 2014.
  6. “Fleas: A Big Problem.” Sergeant’s Pet Care Products, Inc.
  7. Lappin, Michael R., DVM, PhD, DACVIM. “Flea-Associated Illnesses in Cats.” DVM360. June 1, 2005.
  8. Ward, Ernest, DVM. “Tapeworm Infection in Cats.” VCA Hospitals. 2009.
  9. Coffin, Anna M., DVM. “4 Health Problems Fleas Cause in Cats.” Guthrie Pet Hospital. March 4, 2017.
  10. Hendrix, Charles M., DVM, PhD, and Ed Robinson, VT. Diagnostic Parasitology for Veterinary Technicians. Elsevier Health Sciences. 2014.