Last Updated: 14/07/2026
What Do Fleas Look Like on Dogs (And How to Check)
Is your dog scratching? Learn how to tell if fleas are the problem.
Author: Dr Jenny Eales BVSc (Hons)
Reading Time: 7 minutes - short read
Wondering whether your dog has fleas? You're not alone. Every year, millions of dogs suffer from the discomfort of flea infestations. Often the first clue is a dog who just can't stop scratching. Fleas are more than an itch, though. Left untreated, an infestation can lead to hair loss and skin infections, and because these tiny parasites breed so fast, a handful can quickly take over your dog, your other pets and your whole home. The good news? Fleas are very manageable once you know what to look for. In this guide we'll cover how to tell if your dog has fleas, so you can get started on the right treatment sooner rather than later. Ensuring your dog stays comfortable and your home stays flea-free. For a more in depth look at fleas on dogs check out our vet guide.
Flea basics
Fleas are small, wingless, bloodsucking insects that live on your dog's body and lay eggs in the environment. They feed on the blood of animals and humans. After a blood meal the females lay eggs either on the host animal (which fall off into the environment) or in the environment nearby, where the rest of their life cycle takes place.
Believe it or not, the flea that you are most likely to find on your dog is the cat flea (Ctenocephalides felis). The dog flea (Ctenocephalides canis) is much less common in Australia, but is occasionally found. Despite your best efforts, your dog may become infested with fleas through contact with other animals, or fleas that are roaming around in the environment. Read our vet guide to learn more about how dogs get fleas.
There are four life stages of a flea: egg, larvae, pupae and adult. Of all these phases, only the adult phase occurs on the host (your dog!). Eggs are laid in the environment - particularly in soft warm fabric such as carpets, pet beds, and blankets. This is why it's so hard to get rid of fleas: a new wave of juvenile fleas can emerge after you've killed the initial population with a flea treatment.
What are the symptoms of flea allergy in dogs?
Fleas don't just annoy dogs, they can also spread disease to dogs and other animals, as well as humans. They carry the flea tapeworm, which your dog can get as they groom themselves and ingest the flea. Heavy flea burdens can cause anaemia (especially in young, sick or elderly dogs) and intense itching in pets. Dogs with flea allergy dermatitis are especially affected.
Flea allergy dermatitis (FAD) is a condition in which dogs are allergic to the saliva of fleas. It can develop at any age and results in excessive itching, scratching and hair loss which can lead to wounds caused by self trauma, and skin infections.
- Hair loss
- A red rash or small red pimples or bumps
- Small scabs
- Thickened or discoloured skin
- Scratches or wounds from self trauma
- Fur stained brown, which is saliva staining from them licking constantly
These signs are usually seen along the lower back and base of the tail, the thighs and the belly, but in severe cases can be seen all over the dog.
If these symptoms are left untreated, your dog may lose more hair and continue to traumatise and damage their skin. Licking and chewing constantly leaves moisture on the skin that can lead to yeast and bacterial infections, such as "hot spots" or pyoderma, which need veterinary treatment. It is also very distressing for dogs to be constantly itchy, and can affect their mental wellbeing.
How do I check my dog for fleas?
You can usually see signs of fleas (but not always the fleas themselves).
1. Visual check
Fleas are tiny red-brown ovals, only 1 to 3mm long, and they're quick. So don't be surprised if you never actually catch one in the act.
Your best bet is to look over your dog's rump and around the base of the tail, their favourite hangout. Don't assume your dog is in the clear if you don't see any. Fleas are sneaky, and it's often easier to find the evidence they leave behind (flea dirt).
2. Flea comb
A flea comb has very finely spaced teeth designed to trap fleas, eggs and flea dirt. To use one:
- Start at your dog's head and comb towards the tail, following the direction the fur grows.
- Check the comb after each stroke for fleas or flea dirt.
Flea dirt is exactly what it sounds like: small, dark brown to black crumbly specks. Flea dirt is actually flea faeces made up of digested blood, which is why it turns rusty red when wet.
3. White towel test
This is the clincher for confirming flea dirt, and there are two easy ways to do it:
- Stand your dog on a white towel or sheet and give them a good brush. Mist any brown or black specks that drop off with a little water. If they turn red or rust-coloured, you've found flea dirt.
- Or comb your dog with a flea comb, tip whatever collects onto a white paper towel, and spray with water. That same red-rust colour change is your confirmation.
When to seek help
If your dog has fleas, do you need to take them to your vet? It is recommended to do so if the following occurs:
- If you cannot get your dog's flea infestation under control
- If you suspect your dog has a flea allergy
- If your dog is extremely itchy and you are worried they will injure them self
- If your dog has scratched themselves so much that they have a rash, areas of fur loss, or skin wounds/infections
Learn more about how to treat flea infestations.
Does my dog have fleas or allergies?
There are tests available to confirm flea allergy, such as intradermal skin testing which is usually performed by specialist veterinary dermatologists. There are also some blood tests available to check for allergies.
In most cases, FAD can be diagnosed using the dog's history and examining the clinical signs the dog has (such as itchiness and fur loss in the "flea triangle" (the middle of the back to the tail base and the rear legs)).
Other causes of itchiness in dogs include (but are not limited to) the following:
• Contact allergies
• Atopic dermatitis
• Other parasites like mites
• Fungal infections (e.g. ringworm)
What do flea bites look like on dogs?
Flea bites usually show up as small, raised red bumps, often in little clusters, most commonly over your dog's lower back, tail base, belly, groin and back legs. Under all that fur they can be tricky to spot, so you'll often notice the scratching before you notice the bites themselves.
Most dogs feel only mild irritation from a bite. But dogs with flea allergy dermatitis react to proteins in the flea's saliva, and even a single bite can trigger intense itching, redness, scabs and hair loss, especially around the rump and tail.
See your vet if the skin looks broken, infected or crusty, or if the itching doesn't settle once fleas are treated.
It is important to make sure your dog is on a reliable flea prevention year round, to break the flea cycle.
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History
Our experts continually monitor the health and wellness space and we update our articles when new information becomes available.
Tue Jul 14 2026
Edited by Dr Olivia Clarke BSc BVMS MANZCVS (Unusual Pets, Avian)Dr Jenny Eales BVSc (Hons)
Contributing Author, BVSc (Hons)
Dr Jenny cares deeply about the welfare of animals. She's helped Pet Circle pet owners with some great articles and advice!
