Flea Dirt Explained: How to Spot and Get Rid of It

Fleas aren’t just annoying, causing your dog or cat to feel itchy, they can also transmit tapeworms, spread Bartonella bacteria, and cause anemia—they can bite humans, too. Whenever you see flea dirt on dogs or cats, it’s a key indicator that there are fleas that need to be eliminated. 

There are easy ways to determine if your pet has flea dirt, and there are products formulated for canines and felines that will kill fleas and prevent future infestations. 

What is flea dirt?

When a flea bites an animal, it eats blood that ends up digested and released in the form of flea dirt. In other words, flea dirt is feces, and it contains digested blood. 

Adult fleas produce flea dirt. After they mate and lay eggs, larvae will hatch and eat the flea dirt to survive. The larvae then become pupae before hatching from cocoons as adult fleas. 

This cycle continues until you eliminate all the eggs, larvae, pupae, and adults from your pet and environment.  

What does flea dirt look like? You’ll notice small, dry, black specks that resemble ground pepper or coffee grounds. Also, unlike regular dirt that doesn’t change color when wet, if flea dirt gets wet, it will turn red-brown (it’s digested blood, after all). 

How to test for flea dirt

Not sure if you’re dealing with regular dirt or flea dirt? Here’s a simple way to tell the difference: use a flea comb to collect the dirt from your pet’s coat, and then wet the dirt to see if it changes color. 

You could do this by wetting a white paper towel and laying it flat on a table. Place one or more pieces of the dirt on the damp towel. Or, you could place the dirt on a dry paper towel and drip some water on it. 

If you have flea dirt, the specks will turn reddish in color and stain the paper towel red. If you were to smear the dirt across the towel, it would leave a reddish trail. This is the blood the flea consumed. On the other hand, if the dirt doesn’t change color or doesn’t leave a stain after about a minute or so, it’s just regular dirt.

Where is flea dirt commonly found?

Photo by Marcus Urbenz on Unsplash

You might be able to spot flea dirt on your pet if they have lighter colored fur or a thin coat, but oftentimes it’s difficult to see. Use a flea comb to remove any dirt that’s in the coat or closer to your pet’s skin—this type of comb can also grab fleas.

Flea dirt is typically found on warm areas of the body and those that are harder for your pet to reach and groom, such as the base of the tail, hind legs, ears, belly, and neck. 

In addition, you might see the dirt after grooming your pet, even if you aren’t using a flea comb. And you might notice flea dirt around the house, such as in your pet’s bed, on furniture, or on your floors.  

Check your outdoor space for evidence of fleas, too. Even if you have an indoor cat who never goes outside, you can track fleas into your home if they jump onto you. When outside, fleas are typically found in humid, shaded areas, but they’re so tiny that they can be difficult to see unless there are a lot of them. 

How to get rid of flea dirt

To get rid of flea dirt, you have to remove the fleas producing it. This includes a multi-step approach to ensure you kill fleas at every stage of their life cycle both on your pet and in your home.

Groom your pet

Use a flea comb to remove as many fleas as possible, along with flea dirt. As you catch fleas in the comb, make sure they don’t jump away. Keep a cup of soapy water nearby and place them in the water to drown them. 

Giving your pet a bath can help eliminate the fleas and wash away flea dirt. 

Use a gentle shampoo made specifically for cats or dogs. If the infestation is severe, you might opt to use a flea shampoo. Select one for your pet’s species—never use dog products on cats or vice versa. Your veterinarian can recommend one that’s right for your pet.   

Photo by Darren Richardson on Unsplash

Use flea treatments 

There are many vet-approved flea treatments made for dogs and cats, including topical solutions and oral medications. Never use a dog product on a cat, and never use a cat product on a dog.  

Carefully choose the flea treatment you’ll use on your pet based on their species, age, and weight. Your veterinarian can provide guidance and recommendations. 

Use flea treatments as directed. Follow the instructions and read the product label for information about possible side effects. Let your vet know right away if your pet has an adverse reaction. 

Examples include:

• Frontline Plus – This topical product kills flea eggs, larvae, and adults. It’s long-lasting (30 days), waterproof, and easy to apply. It comes in a formulation for dogs and another for cats. 
• Capstar – This is a fast-acting oral treatment for quick relief. It starts working in 30 minutes, killing adult fleas. There’s a version for cats and another for dogs.
• Advantage II – This topical product is easy to apply, lasts for 30 days, and kills fleas at all life stages (eggs, larvae, adults). There’s a formulation for dogs and one for cats.     

Note: Some pets might be at greater risk of side effects from certain flea products. For example, researchers found that cats with the MDR1 mutation are susceptible to serious reactions to eprinomectin, an ingredient in some anti-parasitic products. This is another reason why working with your vet is important when selecting a treatment for your pet.   

Clean your home

To tackle a flea problem, you have to get rid of eggs, larvae, and pupae that aren’t on your pet’s body. Flea eggs fall into the environment where they end up hatching into larvae that eventually form cocoons to transition into adults. 

Vacuum thoroughly, targeting areas where your pet spends a lot of time, including furniture. Empty the vacuum after each use to prevent fleas from escaping. Wash all human and pet bedding in hot water to kill fleas and remove flea dirt. 

Aim to clean daily for at least a couple of weeks until the fleas are gone. But if you have a severe flea infestation and can’t control it on your own, consider asking a pest control service for help.

There are also flea and tick products that can be applied to your lawn and outdoor areas if you need to get rid of fleas in your backyard. 

How to prevent flea dirt from returning

Finding flea poop on dogs or flea dirt on cats can be traumatizing. Once it happens, you never want it to happen again, especially since it takes so much effort to get rid of a flea infestation. 

To prevent fleas, and their dirt, from returning:

Use year-round flea preventatives

Fleas can survive in colder temperatures outside, especially if they find a host. So, rather than using flea preventatives only during the warmer seasons, use them year-round. 

Work with your veterinarian to find the appropriate flea preventatives to keep these parasites from infecting your dog or cat. Your vet can recommend the right product based on your pet’s age, weight, and overall health.  

When using flea preventatives, follow the label instructions carefully for your pet’s safety. Read about potential side effects, and keep an eye out for adverse reactions. If side effects occur, let your vet know. 

Some products require a prescription from your vet, while others can be purchased over-the-counter. Options include:

• Bravecto Chews for Dogs – This is an oral chew that starts working within hours and lasts up to 12 weeks. 
• Bravecto Topical for Cats – This product works for up to 12 weeks, so you don’t have to apply it as often as other topical flea treatments.  
• Seresto Collar – This provides long-lasting protection for up to eight months. Watch for reactions in the area of the collar to be sure your pet isn’t sensitive to it. Options include collars for small dogs, large dogs, and cats.  
• NexGard Chewable for Dogs – This chewable is fast-acting and continues working for a month. 
• Revolution – This monthly topical solution is available in formulations for dogs and cats. It can also protect against other parasites, such as ticks, mites, and worms.
• K9 Advantix II – This topical product for dogs repels and kills fleas, ticks, and mosquitoes. Each application works for a month.  

Maintain a clean home and yard

Vacuuming frequently and washing bedding weekly is a good way to prevent another flea infestation. Remember, you and your pet can track in fleas after spending time outdoors, so by maintaining a clean home, you can remove them before they multiply. 

To help prevent a flea infestation in your outdoor space, keep your lawn trimmed and eliminate debris where fleas and their hosts (e.g., rodents) can thrive. 

Regular flea checks

Even if you’re using flea preventatives and cleaning often, check for fleas regularly. Comb through your pet’s coat with a flea comb, and look for flea dirt in their fur and in areas of your home where they spend a lot of time. 

Also keep an eye on your pet for symptoms of fleas, such as scratching and biting at the skin.  

Conclusion

Bottom line: if there’s flea dirt, there are fleas. Keeping your home clean and using flea preventatives are ways to keep these parasites at bay. Your vet can help you choose the best flea product for your pet, and can provide guidance if flea dirt persists despite treatment.