dog scratching

Fleas on Dogs: Everything You Need to Know

Last Updated 4 APRIL 2024

This article is written by our veterinarian, Dr Michelle Wong BVSc.

Fleas are more than just a nuisance for dogs - they can cause serious discomfort and health issues. Understanding these pesky parasites is crucial for every dog owner, especially considering that fleas can be active all year round in warmer climates like Australia.

In this comprehensive guide, we'll delve into everything you need to know about fleas on dogs, from their life cycle and how they spread to the signs of infestation and the best methods for prevention and treatment. Whether you're a new pet owner or a seasoned dog lover, this article will equip you with the knowledge to protect your furry friend from these persistent pests.

What are Fleas?

animation of fleas in a dog's coat

Fleas are tiny parasitic insects that feed on the blood of pets and cause itchy skin irritation. Fleas do not have wings to fly but they are able to leap up onto the skin and coat of dogs and cats. These parasites prefer hosts with fur, aka your pets, as the thick hair provides protection and allows them to successfully reproduce. 

Do dogs and cats have the same fleas?

The cat flea (Ctenocephalides felis) is the most widespread flea species which can attack both cats and dogs. The dog flea (Ctenocephalides canis) can also cause a similar infestation.

Signs of Flea Infestation

Have you noticed your dog scratching frequently? Does the coat appear speckled with dirt, or perhaps looking a little patchy? Constant itching, hair loss, presence of live fleas and flea dirt are common symptoms of a flea problem. Skin irritations and allergic dermatitis can occur due to flea bites. The skin may be red and inflammed, and could get progressively worse (ie. scratching until bleeding or becoming infected) if not treated.

Can fleas make dogs sick?

In severe infestations, a heavy load of fleas regularly feeding off a dog’s blood can lead to anaemia if left untreated. Fleas can also carry the flea tapeworm which could be transmitted to their host.

How do I know if my dog has fleas or allergies?

Constant skin irritation and scratching, along with spotting fleas in your pet’s coat, is a classic telltale sign of a flea problem.

Always make sure that your dog is up to date on reliable flea prevention, check their coats regularly for active fleas or flea dirt, and be sure to visit your vet if you notice itching, redness of the skin and hair loss. 

With a flea infestation, you may easily find adult fleas moving around your pet’s fur as you part the coat to take a look. Or you may find speckles of ‘dirt’ which are actually flea droppings. Flea combs can be useful when examining your pet for fleas. These combs can help brush out small fleas, flea dirt as well as other debris from their coats. 

If your dog is on regular flea protection and their coat appears clean, it is less likely that fleas are going to be causing their skin issues. There are a wide range of other reasons for dogs to scratch. Allergies can be common in dogs, and there are many forms of allergies such as contact allergy, food sensitivity or environmental allergy (atopy)

How Do Fleas Spread

Fleas can spread by jumping from host to host, from pet to pet, and yes, humans can even get fleas from dogs, though because we are not a flea's preferred host, they don't tend to stick around on us.

Fleas could be anywhere, all year round, although they do tend to thrive in warmer climates so there is often increased flea activity and larger populations with the right temperatures. 

This does mean that even if your dog does not come into contact with another animal with fleas they can still get fleas even just being at home and in the backyard. Other potentially risky scenarios involve going to the groomers, vet clinics, moving into a new house that previously had pets or using second-hand furniture. 

There are many ways for dogs to get fleas (and in every season including winter) which is why it is important to maintain regular flea protection all year round.

Flea Life Cycle

The flea life cycle involves four stages: egg, larva, pupa, and adult. The adult female flea can lay up to 50 eggs a day! Clearly, fleas are able to increase their population size rapidly. Fleas are also very resilient and in their pupae stage they can remain dormant for up to 6 months before emerging as adult fleas.

Flea eggs are laid in the coat which then fall off into the environment. Larvae fleas hatch out and burrow deep into places like your sofa, pet bedding, clothes, carpet and the cracks in your floors. Once safely hidden away, the larva forms a cocoon beginning the pupal stage. As a pupae, they lie in wait for the right conditions. They can detect when a potential host is nearby. The adult flea will be stimulated to hatch and ready to latch on to the new host and feed straight away.

lifecycle image of the flea

How long do adult fleas live? 

Adult fleas can live up to 2-3 months. You can imagine the large number of eggs they can produce during this time (each flea can lay thousands of eggs) and the flea cycle continues in strength if treatment is not applied.

Treating Fleas on Dogs

Use an effective and reliable long-lasting flea treatment to quickly get on top of the flea infestation and maintain ongoing control by giving this treatment regularly. Oral flea tablets such as Nexgard, Simparica or Bravecto are excellent products to treat fleas. 

Capstar tablets work especially quickly to kill adult fleas (within half an hour) but are only effective for about 24 hours. These can be used for swift reduction of fleas on your dog before starting a long-lasting treatment.

Spot-on flea treatments like Advantage, Advantix or Advocate may be used. Always check the label for the proper application method and bathing recommendations to ensure maximum efficacy as this may have an impact. Find out more about the different spot-ons and when it’s best to wash your dog before or after applying flea controls.

Shampoos can be helpful in removing fleas and flea dirt physically from the coat. Frontline spray may be used for young animals (from 2 days old).

Besides the use of flea treatments, it is important to treat the environment as well. Thorough cleaning of bedding, blankets and vacuuming could help to remove lurking fleas. Follow our vet guide on how to get rid of fleas in dogs.

Protecting Your Dog from Fleas

The best way to prevent a flea infestation is to provide continuous parasite prevention. Treat all pets in your household for effective control. Maintaining good hygiene practices and regular cleaning can help reduce numbers of fleas in the environment. 

Not sure which parasite preventative is right? Learn about the best flea and tick treatments for pets in Australia and find one that is suitable for you.

Consulting Your Vet

Our Pet Circle Vet Squad is available 7 days a week to provide general advice for your pet on which products to use and how to break the flea life cycle, as well as troubleshooting issues such as why your dog is still scratching after administering flea treatment. 

If your dog has signs of dermatitis, redness, hair loss, and severe itching, they will need to see their veterinarian for a physical examination and treatment. Flea allergy dermatitis is a common complication and medications may be needed to treat the inflammation and alleviate the itch to prevent further damage. 


Remember that fleas are everywhere, all year round! Regular flea treatment is crucial. It is the most effective way to stop fleas spreading and preventing an infestation in your home