Fleas are a common problem for dogs, but they are not always easy to spot straight away. These tiny parasites can hide deep within your dog’s coat, causing persistent itching, skin irritation and considerable discomfort before you ever see an adult flea.
Knowing the early signs of fleas can help you act before a small problem develops into a larger household infestation. In this guide, we explain five common signs your dog may have fleas, how to check their coat and what to do next.
Ready to treat and protect your dog? Browse our full range of dog flea and worm treatments, including Bravecto, NexGard Spectra, Advocate and more.
1. Excessive Scratching, Biting or Licking
Frequent scratching is one of the most recognisable signs of fleas in dogs. Flea bites can be intensely itchy, causing affected dogs to scratch, bite or lick their skin more than usual.
Pay particular attention if your dog repeatedly focuses on:
- The base of the tail
- The lower back
- The belly and groin
- The inner thighs
- Around the neck
- Behind the ears
Some dogs may suddenly stop what they are doing to bite at their hindquarters or turn quickly towards an irritated area. Others may spend longer than usual licking or chewing their coat.
Occasional scratching is normal. However, persistent scratching, repeated biting or difficulty settling may indicate fleas or another skin problem that needs attention.
2. Flea Dirt in Your Dog’s Coat
Flea dirt is one of the most reliable signs of an active flea infestation. It consists of digested blood excreted by adult fleas and usually appears as tiny black or dark-brown specks in your dog’s coat.
To check your dog for flea dirt:
- Stand your dog on a light-coloured towel or sheet of paper.
- Use a flea comb to work through the coat.
- Concentrate around the tail base, lower back, belly and neck.
- Place any dark specks you collect onto a damp white tissue or paper towel.
If the specks dissolve and leave a reddish-brown stain, they are likely flea dirt rather than ordinary soil.
You may also find flea dirt in your dog’s bedding, on furniture or in other places where they regularly sleep.
3. Hair Loss or Patchy Fur
Constant scratching, licking and biting can damage your dog’s coat and lead to thinning fur or bald patches. Flea-related hair loss is commonly found around the base of the tail, lower back, hind legs, belly and inner thighs.
You may notice:
- Thinning hair
- Small bald areas
- Broken or damaged fur
- Scabs or crusty skin
- Moist or inflamed patches
- Darkened or thickened skin after prolonged irritation
Hair loss does not automatically mean your dog has fleas, as allergies, mites, infections and other skin conditions can cause similar symptoms. However, patchy fur combined with persistent scratching or flea dirt is a strong reason to investigate further.
4. Red, Inflamed or Bumpy Skin
Flea bites can leave small red bumps and areas of irritated skin. In dogs with flea allergy dermatitis, even a small number of flea bites can trigger a much more severe reaction.
Flea allergy dermatitis occurs when a dog reacts to proteins in flea saliva. Affected dogs may develop:
- Severe itching
- Red or inflamed skin
- Scabs and crusts
- Hair loss
- Open sores
- Secondary skin infections
The lower back and base of the tail are particularly common locations for flea-related irritation. Some dogs may also develop redness across the abdomen, groin or inner legs.
Contact your veterinarian if your dog’s skin is raw, painful, weeping, badly inflamed or showing signs of infection. Treating the fleas is important, but additional veterinary treatment may be needed to settle the skin.
5. Restlessness or Behavioural Changes
Dogs affected by fleas may become restless because they are constantly uncomfortable. A dog that normally sleeps peacefully may begin moving from place to place, waking frequently or struggling to settle.
Other behavioural changes can include:
- Increased agitation
- Sudden biting at the skin
- Difficulty sleeping
- Reduced interest in play
- Irritability when touched
- Reluctance to lie on usual bedding
Some dogs may become more withdrawn, while others may appear unusually clingy or unsettled. Behavioural changes alone do not confirm fleas, but they are worth investigating when combined with scratching, skin irritation or flea dirt.
How to Check Your Dog for Fleas
Adult fleas are small, fast-moving and can disappear quickly into thick fur. A careful coat check is therefore important.
Start around the base of the tail and lower back, where fleas are commonly found. Part the fur and look closely at the skin for:
- Small dark insects moving through the coat
- Flea dirt
- Red bumps
- Scabs
- Hair loss
- Irritated skin
A fine-toothed flea comb is particularly useful for dogs with dense or long coats. Comb slowly and inspect the debris collected after each pass.
Not seeing an adult flea does not rule out an infestation. Fleas spend much of their life cycle away from the dog, and only a relatively small proportion of the total flea population may be living on your pet at any one time.
What to Do If Your Dog Has Fleas
If you find fleas or flea dirt, treat the problem promptly. Fleas reproduce quickly, and eggs can fall from your dog into carpets, bedding, furniture and cracks in the floor.
Use an Appropriate Dog Flea Treatment
Choose a treatment suitable for your dog’s age, weight and health. Options can include:
- Oral flea chews
- Spot-on treatments
- Flea and worm combination products
- Long-lasting flea treatments
- Flea collars
Popular dog flea treatments in New Zealand include Bravecto, NexGard Spectra, Advocate and other weight-specific products.
Always weigh your dog accurately and follow the product label. Never use a cat flea treatment on a dog or combine parasite treatments without first checking that they can be used together.
Treat Every Pet in the Household
If one pet has fleas, the other cats and dogs in the home may also need treatment. Leaving one pet untreated can allow the flea life cycle to continue.
Only use products designed for the correct species. Some dog flea treatments are dangerous to cats, so always check the label carefully.
Clean Your Dog’s Environment
Most of a flea infestation develops in the environment rather than directly on the dog. Eggs, larvae and pupae may be present in bedding, carpets, furniture and sheltered areas.
Helpful steps include:
- Vacuuming carpets, rugs and furniture thoroughly
- Washing pet bedding on a hot cycle
- Vacuuming underneath furniture and along skirting boards
- Emptying the vacuum outside after use
- Treating the home with a suitable environmental flea product when necessary
Continue cleaning regularly, as immature flea stages may keep emerging for several weeks after treatment begins.
Maintain Ongoing Prevention
Regular flea prevention is much easier than managing an established infestation. Fleas can remain active indoors throughout the year, particularly in warm homes, so prevention should not necessarily stop when summer ends.
Choose a treatment schedule you can maintain consistently, whether that is monthly or every three months.
When Should You See a Veterinarian?
Seek veterinary advice if:
- Your dog has severe itching or widespread hair loss
- The skin is raw, infected or painful
- Your dog appears weak or unwell
- A puppy has a heavy flea burden
- You are unsure which treatment is suitable
- Fleas continue despite correct treatment
- Your dog has a history of medication reactions or neurological problems
Very young, elderly or unwell dogs may require additional care. Heavy flea infestations can also contribute to anaemia, particularly in small puppies.
Shop Dog Flea Treatments
Explore our range of dog flea and worm treatments and choose the option that best suits your dog’s age, weight and preferred treatment schedule.
- Shop Bravecto Spot-On for Dogs
- Shop Bravecto Chews for Dogs
- Shop NexGard Spectra for Dogs
- Shop Advocate for Dogs
- Shop all Dog Flea and Worm Treatments
This information is provided as general guidance only. Always follow the product label and consult your veterinarian if your dog has ongoing symptoms, damaged skin, an underlying health condition or is taking other medication.