Is it normal for puppies to lose patches of fur?

Some coat change is normal as a puppy's adult coat comes through, and this can look patchy without being a health issue. If the skin underneath looks healthy, with no redness, scabbing or intense itching, it's often nothing to worry about, but get it checked if you're unsure.

Is ringworm dangerous to humans?

Yes, ringworm is contagious between animals and people despite its name — it's a fungal infection, not caused by a worm. If your puppy has circular bald patches and anyone in the household develops similar itchy skin, mention this to both your vet and your GP.

Can fleas cause bald patches in puppies?

Yes, flea allergy dermatitis is a common cause of hair loss and irritation, particularly around the base of the tail and back legs, even from a relatively small number of fleas in a sensitive puppy. Regular flea prevention appropriate for your puppy's age and weight helps reduce this risk.

Will demodectic mange clear up on its own?

Many puppies carry the mite responsible without any problem, and mild, localised cases sometimes resolve as the immune system matures, but it can also need veterinary treatment, particularly if it spreads. Have it checked rather than assuming it will clear up unaided.

How long does puppy coat change last?

It varies by individual puppy and breed, generally taking place over several weeks to a few months as the adult coat comes through. If patchy hair loss continues well beyond that, or the skin looks unhealthy, get it checked rather than assuming it's still just coat change.

Bald patches on a puppy — what could be causing it?

Bald patches on a puppy have a range of possible causes, from completely normal coat changes as their adult coat comes through to mites, ringworm, fleas or friction from a collar or bedding. Most causes are treatable, but the only way to tell them apart is a vet actually looking at your puppy, so any noticeable hair loss is worth getting checked rather than waiting to see.

Usually not urgent

This is common and often manageable at home — but see a vet if it persists, gets worse, or comes with other changes.

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Normal coat change versus something that needs attention

Puppies commonly go through a coat change as their soft puppy fur is replaced by their adult coat, sometimes called the 'puppy uglies', which can look patchy or uneven for a while without being a health problem at all. This is more noticeable in some breeds than others and generally resolves on its own over weeks to months.

The difference between this normal process and something that needs treating usually comes down to whether the skin underneath looks healthy — normal coat change doesn't typically come with redness, scabbing, intense itching or an unpleasant smell, whereas those signs point towards a cause that needs proper attention.

Common causes worth knowing about

Demodectic mange is caused by a mite that many puppies carry in small numbers without any problem, but which can cause localised bald patches, often around the face and legs, in some individuals — this is usually not contagious to other pets and often resolves with time or treatment.

Sarcoptic mange, ringworm and flea allergy dermatitis are other common causes, each with a different pattern: sarcoptic mange is intensely itchy and contagious, ringworm often produces distinctive circular patches and is contagious to other pets and people, and flea allergy shows up as hair loss and irritation particularly around the base of the tail and back legs.

Friction from a collar, harness or bedding, and occasionally a reaction to a new shampoo or product, can also cause a localised bald patch in one specific spot, which is often the easiest of these causes to identify simply from where it appears. Checking whether a collar fits properly, or swapping to a different bedding material for a week or two, is a reasonable first thing to try if the pattern points that way.

Nutritional causes are less common than the ones above but worth mentioning: a poor-quality diet lacking key nutrients can occasionally show up as a dull coat or thinning fur over time, though this is a slower, more general process rather than the sudden, well-defined patches that mites, ringworm or friction tend to produce.

Red flags that mean don't wait

Get your puppy seen promptly if the bald patches are spreading quickly, if there's redness, scabbing, crusting or an unpleasant smell, if your puppy seems intensely itchy or uncomfortable, or if anyone else in the household — human or animal — starts developing itchy skin patches too, since ringworm is contagious between species.

A puppy who seems generally unwell alongside the hair loss — lethargic, off their food, or otherwise not themselves — should be seen quickly regardless of how the skin itself looks, since that combination points to something more than a purely local skin issue.

What a vet visit typically involves

Your vet will examine the affected area and may take a skin scrape or hair sample to check for mites or fungal infection under a microscope, since several of the common causes look broadly similar to the naked eye but need different treatment. This is a routine, quick procedure rather than anything invasive.

Treatment depends entirely on the cause identified, which is exactly why a proper diagnosis matters rather than guessing and trying a home remedy — some causes clear up with simple treatment while others, left untreated, can spread or worsen. Bring along any notes on when you first noticed the patches and whether they've changed, since that timeline can help your vet narrow things down.

What can help

Things we stock that owners commonly use alongside a vet’s advice — not a substitute for it.

Microfibre Pet Drying Robe

A super-absorbent microfibre drying robe that soaks up the wet fast after baths, swims and walks.

From£10.99

Absorbent Microfibre Dog Drying Robe

A super-absorbent microfibre drying robe with a handy front pocket to dry your dog off fast.

From£13.99

Large Self-Cleaning Slicker Brush for Mats and Tangles

A self-cleaning slicker brush with fine, bead-tipped wire pins that gently lift loose undercoat, mats and tangles from short or long-haired pets. A one-click button releases the collected fur for fuss-free cleaning. Cat-ear shaped design.

£18.99

Common questions

Is it normal for puppies to lose patches of fur?: Some coat change is normal as a puppy's adult coat comes through, and this can look patchy without being a health issue. If the skin underneath looks healthy, with no redness, scabbing or intense itching, it's often nothing to worry about, but get it checked if you're unsure.
Is ringworm dangerous to humans?: Yes, ringworm is contagious between animals and people despite its name — it's a fungal infection, not caused by a worm. If your puppy has circular bald patches and anyone in the household develops similar itchy skin, mention this to both your vet and your GP.
Can fleas cause bald patches in puppies?: Yes, flea allergy dermatitis is a common cause of hair loss and irritation, particularly around the base of the tail and back legs, even from a relatively small number of fleas in a sensitive puppy. Regular flea prevention appropriate for your puppy's age and weight helps reduce this risk.
Will demodectic mange clear up on its own?: Many puppies carry the mite responsible without any problem, and mild, localised cases sometimes resolve as the immune system matures, but it can also need veterinary treatment, particularly if it spreads. Have it checked rather than assuming it will clear up unaided.
How long does puppy coat change last?: It varies by individual puppy and breed, generally taking place over several weeks to a few months as the adult coat comes through. If patchy hair loss continues well beyond that, or the skin looks unhealthy, get it checked rather than assuming it's still just coat change.

Sources

Written against guidance published by UK veterinary and welfare organisations. Always confirm specifics with your own vet.

Written by Matt Garnett, who runs Giddy Pets and is a lifelong pet owner — not a vet. This is general information, not veterinary advice, and it cannot replace an examination by the vet who knows your animal. How we write these guides.