Is it normal for puppies to lose their puppy coat?

Yes, most puppies shed their soft puppy coat as their adult coat comes through, which can look like patchy thinning rather than an even, all-over change. This is normal and does not need treatment, but if the skin underneath looks sore or your puppy is scratching a lot, get it checked to rule out something else.

Can puppy food cause hair loss?

It is possible in some cases if a puppy's diet is genuinely missing something they need, but it is one of the less common causes compared with fleas, mites or ringworm. Speak to your vet before changing food based on hair loss alone, since diagnosing the actual cause first avoids swapping foods unnecessarily.

How do I know if my puppy has fleas if I can't see any?

Fleas can be present even when you have not spotted one, particularly early on. Look for small dark specks in the coat, especially around the tail base, which can be flea dirt, and check for scratching, chewing, or small scabby bumps on the skin. Your vet can confirm it quickly if you are unsure.

Is ringworm dangerous to my family if my puppy has it?

Ringworm can spread to people and other pets, so it is worth having your puppy checked and treated promptly rather than waiting. Wash your hands after handling your puppy and avoid close skin contact until your vet has confirmed what it is and started treatment.

Why is my puppy losing hair?

Puppy hair loss has a handful of common causes, ranging from harmless to something that needs treating, and the pattern of the hair loss and what comes with it matter more than the hair loss alone. A few causes clear up on their own; others, particularly anything involving parasites or a skin infection, need a vet to look at your puppy directly.

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.

Find an out-of-hours vet·Search vets near you

Common, usually harmless causes

Puppy coats change as they grow, and some patchiness or thinning while an adult coat comes through is normal, especially around the face and where a collar or harness sits. Friction from rubbing against bedding, furniture or other puppies during play can also thin hair in specific small patches without anything else being wrong.

A recent stressful event — a house move, a new home altogether, or a vet visit — can occasionally trigger a temporary shed in young dogs the same way it does in adults, and this usually settles within a few weeks without needing treatment.

Parasites are a common and treatable cause

Fleas are one of the most frequent causes of hair loss in puppies, particularly around the base of the tail, the belly and behind the ears, and the itching they cause often leads to a puppy scratching or chewing the hair away rather than the fleas removing it directly. Mites causing mange are another genuine cause, sometimes producing hair loss with little visible itching at all, especially around the eyes, muzzle and paws in young dogs.

Both are things your vet can check for directly, usually with a simple examination and sometimes a skin scrape, and both are treatable once identified. Do not assume a puppy is flea-free just because you have not seen one — hair loss and skin irritation can appear before fleas are obviously visible.

Ringworm and other causes worth knowing about

Ringworm, despite the name, is a fungal infection rather than a worm, and it commonly causes small, roughly circular patches of hair loss in puppies, sometimes with reddened or scaly skin at the edges. It is contagious to other pets and to people, so it is worth having checked promptly rather than waiting to see if it spreads.

Less commonly, hair loss in a young dog can be linked to a nutritional gap, a hormonal problem, or a hereditary coat condition that shows up early in some breeds. These are less common than fleas, mites or ringworm, but they are part of why a vet examination, rather than guessing at home, is the reliable way to find the actual cause.

When to see a vet

Get your puppy seen if the hair loss is spreading, if the skin underneath looks red, scabby, or sore, if your puppy is scratching or chewing at themselves a lot, if you can see fleas or flea dirt, or if the hair loss appears in distinct round patches. Hair loss alongside being generally unwell — off their food, low energy, or a change in behaviour — is also worth a same-week appointment rather than a wait-and-see approach.

A single small bald patch in an otherwise bright, happy, normally-coated puppy is rarely an emergency, but it is still worth mentioning at your puppy's next routine check-up if it has not resolved on its own within a couple of weeks.

What a vet visit usually involves

A vet will typically start by looking closely at the pattern of hair loss and the condition of the skin underneath, then examine your puppy for fleas or flea dirt directly. If parasites are not obviously the cause, a simple skin scrape or a sample of hair examined under a light can often confirm or rule out mites and ringworm within the same appointment, without needing anything more invasive.

Bring along anything you have noticed — when the hair loss started, whether it has spread, and whether your puppy seems itchy, since these details help a vet narrow down the cause faster than the hair loss alone. Most causes of puppy hair loss are straightforward to identify and treat once a vet has actually looked, which is the main reason to book an appointment rather than trying to work it out from photos or forums.

Common questions

Is it normal for puppies to lose their puppy coat?: Yes, most puppies shed their soft puppy coat as their adult coat comes through, which can look like patchy thinning rather than an even, all-over change. This is normal and does not need treatment, but if the skin underneath looks sore or your puppy is scratching a lot, get it checked to rule out something else.
Can puppy food cause hair loss?: It is possible in some cases if a puppy's diet is genuinely missing something they need, but it is one of the less common causes compared with fleas, mites or ringworm. Speak to your vet before changing food based on hair loss alone, since diagnosing the actual cause first avoids swapping foods unnecessarily.
How do I know if my puppy has fleas if I can't see any?: Fleas can be present even when you have not spotted one, particularly early on. Look for small dark specks in the coat, especially around the tail base, which can be flea dirt, and check for scratching, chewing, or small scabby bumps on the skin. Your vet can confirm it quickly if you are unsure.
Is ringworm dangerous to my family if my puppy has it?: Ringworm can spread to people and other pets, so it is worth having your puppy checked and treated promptly rather than waiting. Wash your hands after handling your puppy and avoid close skin contact until your vet has confirmed what it is and started treatment.

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.