Signs & Symptoms of Fleas on Dogs

Fleas are insidious, virulent little pests that can cause untold stress and miserable health issues if an infestation is left unchecked, allowing them to proliferate. Because of how quickly a flea can multiply, you could very well be fighting over a quarter of a million fleas in your home just in a thirty-day time period, as they breed, feed, and cycle through their varying stages of life.

The dog flea is very common, in fact, it’s one of two species that are most common in North America. The second species of flea that is very common in North America is the domestic cat flea. But don’t be fooled, even the domestic cat flea can find your dog an attractive host. In fact, many flea infestations that are found in the home and on dogs and cats alike, are the victims of the domestic cat flea, even more so than the dog flea.

No matter the species of flea, all are pretty much equal opportunists. If they can’t find their preferred host to feed on, they will look for the next best host they can find, whether that’s your dog, your cat, a rat, a pig, a squirrel, a rabbit, or even you. If an adult flea doesn’t find a host and feed within its first week of emerging from its cocoon, it will die.

Sometimes they can live a little longer if they are living in the right environment and conditions, but the norm is a week or less. That’s why their burning goal once they become adult fleas is to find a host and start feasting. They need to feast in order to breed and begin the whole four-stage life cycle once again.

What Does a Flea Look Like?

What you will mostly likely find on your dog is an adult flea. These are fully-formed fleas that are red or brownish red in color, with six legs designed to help them jump long distances. They have no wings, but they have a thin, flat-shaped body with backward-pointing hair that helps to keep them attached to the fur of their host.

They have tiny little mouthparts that are like a siphon, designed to help them pierce a dog’s skin and feed on their blood. Though they don’t fly, they can definitely travel far with their jump. Think “tiny blood-sucking, grasshopper” and you may have a better picture of how they navigate from host to host.

You might think your dog having a flea or two is no big deal, but they can quickly become a problem that is out of control, and cause quite a few problems with your dog’s health. Some dogs may even have an allergic reaction to flea bites. If the infestation gets really bad, a dog could even become anemic and dangerously ill.

Does Your Dog Have Fleas?

Sometimes dogs may not show many symptoms of a flea problem. Other times, they will present with a variety of different symptoms. Whatever the signs your dog gives you, if you think they may have fleas, it’s a good idea to check them thoroughly to be sure.

You can do a visual check to start with, because even though adult fleas are small, you should be able to see them if they are running around making a meal out of your dog. Check the areas on your dog where the hair is thin, like their underbelly, their armpits, or on the underside of their back legs. Sometimes you may see them crawling around your dog’s face or ears and they especially like to congregate beneath your dog’s collar and around their neck.

If you can’t find any fleas, or you only find one, try using a flea comb to see how bad things are. You can check the same areas using the comb, making sure to apply pressure to your dog’s skin so the comb picks up whatever may be found. Be careful if your dog has any areas that look raw or painful from scratching. You won’t know if it’s from fleas or not unless you find flea debris, but even if they have some other skin problem, you definitely don’t want to make it worse or cause it to spread.

You will most likely find the comb picks up little black specs of what looks like dirt. This is called “flea dirt” but it’s actually flea feces left behind from adult fleas. It’s a good indicator that you have a flea problem. Make sure you keep a bowl of hot, soapy water nearby while you check your dog, because if you find any live fleas you can pick them off and drown them.

If you don’t have flea comb, you can still check your dog for flea feces. Use a white towel or paper towel and place it under your dog as you brush their fur. Flea feces will drop to the ground and land on the towel, allowing you to see it better.

You can make certain it’s flea dirt by wetting it, the feces will turn red in color. Flea dirt can accumulate in places your dog spends a lot of time as well, such as their bedding or kennel, or that favorite spot they like to lay near the couch.

Usually, if your dog does have fleas, you will find evidence somewhere in the form of live fleas, eggs, and flea dirt. What’s frustrating though, is that even one little bitty flea can cause a severe allergic reaction in your dog and cause them to scratch and itch like mad. Then finding that one flea before it finds a mate and starts reproducing becomes the challenge!

Other Signs and Symptoms of Fleas in Dogs

Though live fleas, flea dirt, and flea eggs are all signs of fleas on your dog, sometimes your dog may experience other symptoms as well. This is usually in response to the bite of the flea. Dogs can develop a health condition called FAD. This flea allergic dermatitis results from an allergic reaction to the saliva of fleas.

When a flea bites your dog, they leave saliva behind. Depending on whether or not your dog is sensitive to this, it could cause severe itching, which can lead to secondary bacterial infections that could turn fatal. Still, other dogs may show no signs of irritation at all, which can be maddening if the fleas have already started proliferating.

dog-flea-4Dogs can also contract other diseases from fleas, like cat flea rickettsiosis and flea-borne typhus, or develop tapeworms from accidentally ingesting a flea. If you notice your dog looks like they have tapeworm larvae in or around their stool or crawling out of their anus, then it’s a good bet they also have fleas.

Other signs that your dog has fleas include excessive itching, chewing, and biting at their skin. You may notice your dog develops redness and irritation, or possibly scabbing, black spots, and pus-filled sores. Sometimes they will develop hot spots and may lose their hair because of how bad the irritation gets, or you may notice areas where their skin looks bumpy and red.

Your dog may act as though they are restless and antsy. Another warning sign you may notice is your dog shaking their had a lot or scratching at their ears. Their ears are a sensitive spot and those flea bites can get painful and itchy.

Unfortunately, the itching and scabbing can lead to secondary infections which can compound the problem and cause your dog’s health to worsen. Some dogs may even become anemic if the fleas are really bad because they are losing too much blood. This is more common in very young pups or much older dogs, but it can happen to any dog at any age if the fleas get bad enough and aren’t treated.

Where Do Dogs Get Fleas?

Unfortunately, fleas are a common environmental hazard, especially in warmer weather areas. Just about any animal can carry fleas and although fleas come in a variety of species and have preferences over their host, it doesn’t stop them from finding their way into your home and onto your dog.

Animals like squirrels, rodents, neighborhood cats and other dogs nearby can all carry fleas and drop them on the ground. That flea is then forced to find another host or die, and your dog may wander by at just the right moment.

Once your dog has picked up a flea, they multiply quickly and can drop eggs and larvae on the floor of your home and make themselves comfy in your carpeting and furniture. Sometimes dogs get fleas because you have a mice problem and the mice are carrying fleas.

And if your dog frequents any areas where other dogs and animals are, their chances of getting fleas increases. Dogs in kennels, doggie daycares and grooming facilities, dog parks, even your local vet’s office can all be places for your dog to be exposed to fleas and bring one home to roost.

Diagnosing and Treating Fleas in Dogs

If you suspect your dog has fleas, you’ll need to check both the dog and your home for signs. Live fleas, flea eggs, flea dirt, these are all visible evidence that your dog is infested. You will find signs of fleas in your home as well, especially areas where your dog spends the most time. This means that not only will you have to treat your dog, but you’ll also have to treat your house too and you probably won’t be able to do any of that successfully without some help from your vet.

dog-flea-2Your vet can give you medication for your dog designed to kill fleas at their most vulnerable stages of life, from adult flea, to egg, to larvae. These medications work over a period of time, killing the live fleas and larvae right away and then killing the new fleas as they hatch. Typically, you will apply these medications to your dog’s shoulder blades and it will spread naturally on its own through your dog’s glands.

Once your dog has been dosed with medication and it’s been allowed to remain on their fur for at least 48 hours, you can bathe your dog and remove any dead fleas, flea dirt, flea eggs, and whatever other irritants that may be left behind. Sometimes an oatmeal bath is great to help soothe your dog’s itchy skin, but make sure it’s safe to use with flea medications.

You don’t want to do anything that counteracts the effects of the flea medication. Sometimes you can give your dog a medication that combats fleas and other parasites too, like ticks. Talk to your vet about the best options for your canine.

After you’ve treated your dog and cleansed them of all visible fleas and evidence of fleas, you need to then treat your home yard. If you don’t, you’ll just be fighting off more fleas and have to treat your dog again and again, because the fleas will be making their home in your home and using your dog to survive and thrive. It’s a vicious cycle, so you can’t skip treating your home and yard.

You can use flea powders and medicated flea sprays to treat your home and carpet, as well as your yard. Make sure you vacuum your home thoroughly, several times if needed, and mop your floors with hot water and your cleanser of choice. Make sure you wash all your dog’s bedding in hot, soapy water, too.

In very severe instances, a licensed professional in pest control may be needed, but most are fairly reasonable in pricing and well worth the investment. Whatever you do, don’t do nothing. Not only will your dog suffer for no reason, but the problem can quickly escalate to unmanageable proportions and make the whole job much harder than it needs to be.


  1. “Fleas in Dogs – Symptoms, Causes, Diagnosis, Treatment, Recovery, Management, Cost.” WagWalking, Wag!,
  2. “Fleas: Detection, Treatment, & Prevention.” Cesar’s Way, 10 Dec. 2015,
  3. “How to Tell If Your Dog Has Fleas.” Hartz, 19 Nov. 2018,
  4. petMD. “PetMD.” PetMD, 25 Sept. 2018,
  5. petMD. “PetMD.” PetMD, 9 Sept. 2016,

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