What Do Fleas Look Like on Dogs?

Michael Kearley, DVM
By Michael Kearley, DVM on Jul. 21, 2022

Most pet parents have witnessed their dog excessively scratching one day, and then realize their dog is also chewing and biting its skin.  What’s the likely cause? Fleas.

Fleas are small, dark brown or black insects that survive by feeding on mammals causing many a sleepless night for pets and pet parents alike. The good news is that fleas can be prevented and effectively killed once discovered on your dog.

How To Tell If Your Dog Has Fleas

Fleas are most active during the warm months but they are very efficient and can thrive year-round. Fleas can contribute to the onset of secondary skin infections and the transmission of multiple diseases and parasites.

Itching, scratching, and biting the skin are often the first telltale signs that your dog has fleas and warrant further looking into, as would hair loss, scooting, “hot spots,” and a copper- or rust-colored coat.

Symptoms of Fleas on Dogs

Other than changes in your dog’s behavior (excessive scratching, licking, and chewing) that may prompt you to check your dog for fleas, the most common signs of fleas are related to the skin. 

Your dog may have hair loss or “hair barbering” (when the hair is chewed off leaving stiff or rough ends), changes in its coat color due to chronic licking or chewing, crusts, scales, redness, and “hot spots” (moist, ulcerative, and often inflamed lesions that appear suddenly). Areas near the lower back, tail, inner thighs, and groin are generally the most affected.

Also, when bitten, dogs may be allergic to the flea saliva and may develop a reaction known as Flea Allergy Dermatitis.

Fleas can also transmit diseases caused by the Bartonella bacteria, as well as parasites such as tapeworms, and even diseases that humans can contract such as murine typhus.

Keep in mind that fleas ingest their host’s blood when they bite, which can also lead to anemia (iron deficiency).

Is It Dry Skin or Fleas?

When your dog has dry skin, you may see scales and flakes that are stationary and white, akin to dandruff in people. Dry skin is also seen in patches.

Fleas, on the other hand, are dark brown or black, crawl around, and can be seen in your dog’s fur one at a time, or in multiples.

How To Check Dogs for Fleas

If your dog shows the signs and symptoms noted above, it’s critical to examine it further for fleas.

Areas that should be examined first are the lower back, tail head, and the back of thighs and groin.

Also, your dog’s crate, bedding, and toys should be checked for fleas.

When conducting a flea check, follow these steps to look for fleas in your dog’s fur:

  1. Part the hair and watch for any signs of flea movement.

  2. Check for black specks, like ground pepper (or flea dirt), which is technically flea feces and partially digested blood from a host. 

  3. Using a flea comb, gently comb the hair and then place any specks trapped in the comb on a white paper towel.

  4. Add a few drops of water on the specks and look for changes in color; if you notice a reddish-brown to red color, then fleas are present.

What Do Fleas on Dogs Look Like?

The flea life cycle consists of four stages: egg, larva, pupa (in a cocoon), and adult. The entire flea life cycle is about three weeks but varies depending on the environment.

Flea eggs are microscopic, white, and oval-shaped. Adult fleas, on the other hand, can easily be seen with the naked eye, and are dark brown or black, and can crawl or jump.

Flea dirt looks like black specks on the skin and fur of your dog.

Treatment for Fleas on Dogs

Follow these three strategies to treat fleas on your dog:

  • Eliminate fleas on your dog: If fleas are seen, or even suspected, you should first contact your veterinarian. Most likely, he or she will recommend or prescribe a product that can be given orally or topically to rid your dog of fleas. It’s important to treat all pets in the home, not just the one with fleas. 

    • Your dog should be examined and treated for any secondary skin infections with antibiotics, shampoos, and anti-itch medications as well as screened for potential diseases or parasites transmitted from fleas. Bathing your dog is also helpful to remove any live fleas and flea dirt.

  • Eliminate the infestation in the environment: Clean or throw away your dog’s bedding, toys, etc. to remove the infestation. Vacuum regularly and pay close attention to floor cracks, tile grout, and hard-to-clean areas. Ask a pest control company for a product that is safe for your family and pets and effective at eliminating fleas. Preventing wildlife or feral animals from entering your property will also help control fleas.

  • Prevent re-infestation of fleas: Certain preventive products given monthly (or less frequently) to your dog contain ingredients that either kill fleas before reproducing, such as Revolution, Frontline Plus, and Sentinel, or break the fleas’ life cycle, such as IGRs (insect growth regulators) such as (Advantage II, Frontline Gold, Vectra 3D).

Prevention of Fleas on Dogs

Preventing fleas on your dog is extremely simple, and flea prevention products are easily accessible and inexpensive. There are many products on the market, and each acts differently in killing and/or repelling fleas and each has a different application process.

Partner with your vet to find the most suitable product for you and your dog’s lifestyle. Oral products such as Bravecto, Capstar, and Comfortis act within hours after being given, while topical products such as Frontline, Revolution, and Advantage take a little longer.

And because fleas can thrive in almost every type of environment, vets recommend giving your dog year-round protection and doing frequent, thorough flea checks on your dog.

What Do Fleas Look Like on Dogs FAQS

Are dog fleas visible to the naked eye?

Yes! Fleas are small, dark brown or black insects that are visible to the naked eye.

What kills fleas on dogs instantly?

There are many products such as Advantage, Capstar, and Comfortis (among others) that quickly kill flea larval and/or adult stages rapidly, some as quickly as 30 minutes.

Can I get fleas from my dog?

Fleas generally won’t leave their host unless groomed off or physically removed, and they most often prefer your dog (or other pets) to you. With severe infestations, however, fleas can certainly jump on you and bite.

Featured Image: iStock.com/Sladic

Michael Kearley, DVM


Michael Kearley, DVM


Dr. Michael Kearley graduated from the University of Florida College of Veterinary Medicine in 2013. He graduated with a certificate in...

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