Treating and Preventing Fleas on Your Pet

Medically Reviewed by Amy Flowers, DVM on March 07, 2019
5 min read

Fleas are no fun. Not for you, since you have to deal with the occasional nip on the ankle and the hassles of ridding your home of the little buggers. And certainly not for your pets, who can bite and scratch themselves raw trying to nail the pesky pests.

If fleas are making your home life miserable, you have two challenges:

  1. Treat your ailing pets by getting those annoying little bloodsuckers off them.
  2. Keep fleas from terrorizing them again.

The scratching, the biting at the fur, maybe even the big patches of irritated skin all point to fleas. A fine-toothed flea comb run through your pet’s fur can confirm it if it picks up adult fleas and maybe some “flea dirt,” little spots that look like pepper.

The "dirt" is actually flea poop, made mostly from your pet’s dried blood. You may be able to see fleas without a comb if you separate the hair between your pet’s shoulder blades or at the base of the tail.

First, check with your veterinarian.

“A lot of those flea prevention products -- as long as they’re not combined with heartworm prevention -- you can get them over the counter," says Atlanta veterinarian Euphrates Anderson, DVM.

The soap in a bath can act as a gentle insecticide. Other problems that come from fleabites -- open sores from scratching or other skin problems like rashes -- may call for stronger kinds of help. Again, see your vet.

“If you’re starting to see some irritation on the pet’s skin,” Anderson says, “that’s when you probably need to schedule a visit with your veterinarian so they can prescribe an antibiotic if there seems to be an infection.”

The medication Anderson suggests after that initial bath is a chemical insecticide designed to kill fleas. So it’s critical to follow the instructions to the letter.

Don't use flea prevention meant for a dog on a cat. That can be life-threatening.

Your pet’s vet can recommend the type of prevention that will keep fleas from hitching a ride on Spot or Fluffy again. It comes in different forms:

  • Topical (like a liquid or gel applied to your pet’s skin)
  • Oral (taken as a pill or treat)
  • Flea collars

Your vet can tell you:

  • How quickly each of these products work (some start killing fleas in 30 minutes)
  • How often each needs to be used
  • How long the treatments last
  • How well it works on your pet

Remember, fleas can be more than just irritating. They can carry the eggs of tapeworms, an internal parasite. Some pets are allergic to fleas and get something called flea allergy dermatitis, where the skin becomes hypersensitive. Too many bites, especially to younger cats and dogs, can cause anemia, a dangerous loss of red blood cells.

“In addition to just being a nuisance, [fleas] can actually cause harm and disease as well,” says Brenda Stevens, DVM, a clinical associate professor in North Carolina State’s College of Veterinary Medicine.

“[They] can be life-threatening.”

Even if you’ve obliterated all the fleas on your pets, you’re not finished. Adult female fleas can lay 25-40 eggs a day. That's up to 2,000 in their lifetime. These eggs quickly drop off into places your pet hangs around. Think carpets, furniture, kennels, cat boxes, and beds. Those eggs hatch into larvae in a few days and become full-fledged, biting adult fleas a couple of weeks later.

“I think some of the mistakes [people make] come out of not using products appropriately. If they are supposed to be applying a product once a month, and they’re being used every 2 months or something like that,” Stevens says.

“But I think not understanding what a product can actually do is a big part of it as well," she says. "If an animal has fleas, the thought is, well, you get a flea shampoo and you’re going to kill the fleas. Well, the shampoo very well may kill the fleas that are on the pet at that time, but it’s not going to do anything to prevent other fleas from jumping on your pet.”

“You’ve actually only just scraped the surface of the problem.”

And that brings us to the second part -- wiping out fleas.

“Whenever we’re treating for fleas, it’s always a two-part component,” Stevens says. “We have to treat the pet, and in addition, we have to treat the environment.”

Keeping fleas under control on your pet and in your home takes:

  • Strict sanitation
  • Pet treatments (like the ones discussed above)
  • House treatments (both indoors and outdoors)

Sanitation is simple. Vacuum -- a lot. Clean and vacuum all over, especially in the hot, humid places fleas and their larvae like to hang out. Do it at the same time you treat your pet.

Flea larvae hide in carpets and are generally immune to insecticide, so vacuuming does a few things:

  • It pulls some of the fleas out of the carpet.
  • Pre-adult fleas are pushed to leave their cocoons.
  • The carpet opens up for treatment by insecticides, which will be effective once the larvae hatch into adults.

Get rid of the vacuum bag or empty the canister -- outside -- when you're done. Otherwise, the larvae will hatch in there. If your vacuum has a canister, after you empty it, wash it out with hot, soapy water.

It helps to regularly clean pet beds -- and any other place flea eggs or larvae may have fallen. Experts suggest cleaning and vacuuming before you use insecticides.

Before you put any insecticides inside your home -- or outside -- check with your veterinarian. Again, these can be toxic if not used properly. Your vet can help you with possible non-chemical methods, too.

“Many of these [chemical solutions] are extremely safe; they work only on certain nerve pathways that insects have that people or mammals do not have. So they’re very, very safe to be around, for people and animals,” Stevens says.

“But I still think it’s always a good idea to be cautious with any type of chemical," she adds. "You would always want to follow the directions, as far as if you need to be out of the room for several hours or that sort of thing.”

Treatments for your home come in many forms, from powders for your carpets to the “bug bombs” that fumigate whole rooms, to sprays, which are more easily targeted. They often have ingredients that kill adult fleas. Many have insect growth regulators, which ward off the growth of the eggs, larvae, and pupae (the stage between larvae and adult, when the little biter-to-be is in its cocoon).

Flea treatment, both for your pets and your home, is not a one-and-done process. If you think you’re finished, you’re not. Researchers estimate that for every adult flea you can see (they’re only about 1/8 of an inch long), there may be as many as 100 immature fleas ready to pounce.

“I think one of the most common mistakes is that a lot of times, pet owners feel as though they only need to treat for fleas in the warmer months,” Anderson says. “But fleas still pose harm even during the colder seasons.

"You have these owners, when it does get warmer, they say, ‘I have a flea infestation,’ and it actually occurs months before when they didn’t have their pet on prevention.”

So your pets need regular treatments, and your house needs regular cleaning.

Spot and Fluffy will thank you.