How Do I Know If My Dog Has Fleas?

  • Written By Dan Edwards on December 14, 2018
    Last Updated: December 30, 2020

Fleas are unpleasant and very active insects which can cause your dog extreme discomfort. These nasty parasites leap aboard your beloved pet, digging through their fur to the skin beneath where they feed upon her blood.

Fleas can cause significant distress, as well as pose a serious threat to your dogs’ health. Knowing how to tell if your dog has fleas is therefore very important for all dog owners.

In this article, we will describe the signs you should look for to determine if your dog has an unfortunate flea problem.

Abnormal Behaviour

Fleas are more than simply gross, annoying parasites. They can cause episodes of extreme itchiness known as “pruritus”, which naturally results in your dog intensively chewing and scratching at themselves in an attempt to relive the irritation.

Just the action of crawling and scurrying around among the fur is enough to upset most dogs. However, within moments of settling into your dogs’ coat, these nasty pests will start to feed upon your dogs’ blood, causing further pain and discomfort. Flea saliva contains a chemical which makes the feeding process easier. It works by dissolving the skin, making it softer and less difficult to pierce. It is this chemical which causes the itchiness which your dog will be suffering after being fed upon.

Some dogs will experience a relatively mild reaction to flea bites, but others can suffer a hypersensitivity reaction. This is basically a particularly severe allergic reaction to the chemical in flea saliva. In these cases, dogs can be driven crazy with extreme itchiness caused by even a few flea bites.

dog scratching fleas

The most common areas your dog will be trying to chew and scratch are the rump, base of the tail, flanks, and areas under the armpits. These are the place which fleas love to hide and feed.

If your dog is licking, chewing and intensely scratching at these areas, it is a sure sign that your furry friend is suffering with some unwelcome residents. Another key sign something is upsetting your dog is if your dog appears relaxed and settled, only to suddenly yelp, leap up and spin around trying to reach its rear end.

It is important to be aware that not all symptoms of flea infestations are physical. Different dogs can react in different ways to the irritation and discomfort caused by flea bites. In some cases, your dog may simply appear restless, grumpy, depressed or just act weird in normal situations.

Moreover, if you have more than one dog in your household, each dog can behave differently when they have fleas. If one dog is intensely itchy and the other is not, this will not mean that only one dog is suffering from fleas. If there are fleas in the house and upon one pet, it is safe to assume that all pets will be carrying these irritating bloodsuckers.

Flea Dirt

Flea excrement is known as “flea dirt”. It appears similar to ground black pepper or coffee grounds. It can be found within the home, as well as nestled amongst your dogs’ fur. Flea dirt is essentially digested blood which has passed through the flea. It will look dark when you first find it, so the best way to be sure it isn’t simple dirt, is to wet it and see whether it changes appearance. Once it has been wet, flea dirt will start to “melt” into a reddish-brown colored stain.

flea dirt on dog
Flea dirt on a dog’s underbelly

The best way to check for flea dirt is by petting your dog while gently and slowly parting the fur in the regions which fleas prefer to settle. The back of the neck is a good place to look, as is the area at the top of the tail. These are also places which your dog is quite accustomed to being petted, which should make the process easier. If you see any black specks clustered together, pick them out and place them onto some damp tissue to see if they are flea dirt.

If your dog has darker fur or skin, it may be difficult to see the flea dirt. In this case, you can check for flea dirt in any areas your dog likes to spend time. A clever trick is to put on a pair of white socks and stomp about your home. If you see any black specks stuck to your socks, you can perform the same damp tissue test to see if you have picked up flea dirt from the floor.

Red/Sore Patches Of Skin

It is not a guaranteed symptom, but a dog which is suffering from fleas will sometimes present visible signs on their skin. As before, the best places to look for skin signs are the base of the tail, back of neck and flanks, as these are the spots your dog can most easily reach to scratch and chew.

By parting the fur, you may be able to see a reddening of the skin, or even little red bumps not unlike pimples. This is the swelling and allergic reaction to a flea bite. In dogs which have a severe response, there may be scabbing or open wounds from self-mutilation.

Flea Hot Spot

Such wounds can present a serious risk to your dogs’ health if they are not treated quickly. Bacterial infections can occur, as well as a form of dermatitis caused by the repetitive skin damage.

Bald Patches/Hair Loss

It is no surprise that the extreme irritation caused by flea bites can lead to your furry friend removing their fur from intensive scratching and chewing. As a result, red bite marks and bald patches are common signs of a flea problem.

flea bites on dog belly
Flea bites on a dog’s underbelly

This fur may grow back in one place only to become under attack again. Fleas do not like to feed or settle in areas where there is no fur to hide amongst. So they will move away from bald areas to cause discomfort elsewhere. In extreme cases, the skin damage caused can result in permanent baldness or thinning of the fur in a particular area.

Finding Alive/Dead Fleas

Fleas actually spend most of their life cycle within the home and not living upon your dog. Therefore, it is recommended to also check your home and yard as best you can to see if you can locate any signs of fleas preparing to set up residence on your pooch.

Flea eggs can fall off your dog into your carpet, as well as being laid amongst the fibers in the first place. Grab a magnifying glass, rake your fingers through the carpet slowly and look for any evidence of flea eggs or flea dirt. Flea eggs look like very small creamy white ovals. They will not adhere to the fibers, instead they will be loosely nestled among them.

flea eggs
flea eggs in carpet
Flea eggs between carpet fibers

Fleas will happily survive outdoors in your yard, while they wait to hop aboard your beloved pet. Great places to check for evidence of fleas are any shaded and moist areas which do not receive sunlight. You do not need to go hunting for fleas with your magnifying glass this time. Simply use the white sock test to check for dirt, dead fleas or even any live ones which have attached themselves to your socks!

Of course, you should check your dog for fleas too! This isn’t always easy, as fleas can be very nimble, leaping away as soon as they sense they will be exposed. They are capable of jumping incredibly long distances, so can be out of sight before you know it.

A fleas hind legs allow them to jump great distances – CC Image courtesy of Clay Nichols

Fleas have flat bodies and are can be as small as 1/16th of an inch long. They are brownish-black in color, although they can be a little lighter if they have recently ingested lots of blood.

To check your dog for fleas, encourage them to lay down and go through the fur from the back of the neck to the base of the tail, before checking their underside. You will need to look out for any little black-brown specks which are there one second and gone the next! Be sure to inspect for any raw, spotty or bald patches on their body too.

The most convenient way to check for fleas on your dog is by using a flea comb. These are very fine-toothed combs which catch fleas, eggs and flea dirt from amongst your dogs’ fur. It is important that you get close to the skin when using these combs, to ensure you do not miss any sneaky fleas.

flea comb hair

Keep a bucket of soapy water nearby to wash off the comb in-between sections, or when it becomes full of loose hairs. You should see black specks in the water if your pooch is suffering from fleas. Leave the water to stand for a while to ensure all the fleas have drowned before disposing of the contents outside.

Another good tip is to use a sheet or an old white towel under your dog as you comb, this will make any fleas which fall off much easier to spot. Make sure to squish them as soon as you see them!


When fleas decide to move into your home, they are certainly an unpleasant and unwelcome addition to the lives of both owner and dog. They are very hardy creatures which unfortunately require dedicated effort to eliminate.  

Before attacking your home and dog with potentially unnecessary flea treatments; it is advised to make sure that fleas are in fact the problem which you are facing. With the advice we have provided in this article, you now know how to tell if your dog has fleas and attend to the problem before it becomes out of control.