The majority of dogs have 18 nails (or claws) – four on each foot and two front dew claws – and sometimes more if they have rear dew claws or extra digits! Each one of these nails grows continually and has the potential to break or split, and it’s a common reason for caregivers to worry that they might need to see a vet. This article gives an overview of common causes of split nails, and when you might need to see a vet for help with this.
Anatomy of the foot and nails
Dogs have four toes (digits) on each foot, corresponding to human fingers. Each toe has 3 bones inside it, and the claw is an area of modified skin attached to the end of the third bone. The claw is a hard growth of horny keratin that forms a wall protecting the tender tissue underneath (often known as ‘the quick’). The quick has a good blood supply and will bleed if cut. The claw naturally wears on contact with the ground as the dog walks.
You can find a good diagram of the anatomy here.
‘Dew claws’ are the equivalent of the thumb and are located about a third of the way between the foot and the elbow, usually firmly attached to the leg. It is normal to have dew claws on the front legs, but some dogs will also have them present on the hindlegs. For some breeds, such as the Pyrenean Mountain dog, having extra dew claws is considered part of the breed standard! Dew claws do not wear down when walking as they do not contact the ground, but most of the time this is not an issue as they do not grow as fast as nails on the digits. They are however more likely to get damaged as they stick out to the side more.
Issues with just one claw
Traumatic Nail Splits
Far and away the most common cause of split nails in dogs, trauma to the nails usually happens when your dog is out having a lovely time running but accidentally catches the nail on something. Sometimes they will cry out, sometimes they will be lame, but sometimes you will have no idea this has happened until you find the hard nail casing on the floor or realise that they are licking at their foot a lot.
If your dog will let you look, you may see the nail bent back or sticking out at a funny angle, still attached at the base. Be careful as many dogs will get grumpy about this, even those that are normally very friendly! If the nail seems very loose, your dog may allow you to remove it, but if in doubt make an appointment to see your vet. With gentle restraint from nurses (and hopefully some treats as a distraction), your vet will usually be able to safely remove the fragment in a normal appointment, and provide pain relief if necessary. Most of these cases will not need antibiotics, and the nail will naturally grow back on its own over a few weeks.
Some nails split longitudinally from the tip to the base, and this is more difficult to treat in the conscious dog as it is more painful. Your vet will usually recommend sedation or a short general anaesthetic in this case so that the attached nail can be peeled back (a bit like a banana!) so that a new healthy nail can grow back.
If your dog splits a nail overnight or when your vet is shut, it is not normally an emergency. Washing the paw in saltwater (around 1 teaspoon of salt in a pint of water) and making sure your dog does not chew or lick at the paw is usually enough to provide first aid until your vet opens. If there is lots of blood however or your dog is distressed, it’s always best to call for advice.
Nail fold infections after trauma
As with skin anywhere on the body, the nail folds are covered with bacteria and yeast organisms that are meant to be there. If your dog chews excessively at these areas (for example, at the base of a torn nail that has not been removed), these bugs can overgrow and cause a secondary infection in the fold, characterised by red inflamed skin and a pale smelly discharge. These areas will be very sore and your dog will only want to chew more so get them to your vet for treatment. This will involve dealing with the claw, but antiseptic or antibiotic treatment may also be required.
Ingrown claws
Claws grow throughout life (as long as the tissue underneath is not damaged) and are designed to naturally wear down to a flat surface as the dog walks. If for any reason this does not happen (lack of exercise being the most common cause), then the claw grows out and round into a point. This point can grow so far that it digs into the soft pad on the underside of the foot, causing lots of pain. This can also be a source of infection.
The quick inside will also continue to grow and get longer as nails grow. This sometimes means that a nail cannot be cut as short because the quick would then also be cut and bleed.
Some breeds are more prone to longer nails than others, and if your dog cannot exercise for any reason then the claws will grow longer. However, there is never a need for a dog to have ingrown claws as regular trimming immediately resolves the issue.
Issues involving more than one nail
You may sometimes realise that it is not just one nail that is split, but several over the same foot or even all four feet. This usually means that the underlying cause is affecting the whole body, and as such is something worth asking your vet about.
- Some dogs seem to bite or lick their nails, much as a human would do. Sometimes this can be a sign of boredom or stress, but more often it means your dog is itchy, with parasites or allergic skin disease being the most common causes.
- Sometimes one or more nails will slough and fall off without any apparent trauma first, and when they regrow they may seem softer or misshapen. This is often associated with auto-immune disease, and will need a biopsy to confirm diagnosis before starting medication to stop the body attacking itself.
- Many hormonal diseases can be associated with poor nail quality and more frequent issues, including underactive thyroid glands (hypothyroidism) and overactive adrenal glands (Cushings disease). Your vet will be wanting to know about any recent changes in weight, appetite and drinking habits, and will recommend blood tests to assess for these conditions.
- Some infectious diseases can be associated with changes in the nails, making them more likely to split. This can be of particular concern in dogs not born in the UK. Distemper is a viral condition covered against in routine vaccinations in the UK, but is starting to be seen again due to increasing numbers of imported dogs. Leishmaniasis, a protozoal infection transmitted by sandflies, causes lifelong issues with not just the skin but many other body systems including the kidneys.
- There are some developmental conditions that are associated with the nails, most of which are present from when your dog is a puppy. Extra digits and claws are not as rare as you might think!
- As with humans, general health is associated with the quality and health of the nails. Nutritional deficiencies (associated with poor diet choices) are rare in dogs but can cause extreme signs.
Nail care at home
Sometime nails will inevitably become overgrown despite good exercise levels. This is often breed related (pugs, dachshunds and bulldogs being especially at risk), and can be associated with other diseases that mean your dog is less active, such as arthritis.
Look at your dog’s feet with as they stand square on a flat surface – you should be able to slip a piece of paper underneath the nail. If you can’t and the nail extends beyond the pad to touch the floor, then it is too long and needs trimming. Another tell-tale sign a manicure is needed is if you can hear the nails ‘clicking’ as they run along a hard floor!
Little and often is the best way to trim
You can use dog nail clippers or specialised electric dremel tools, which act more like a nail file. The most important thing is to make it a positive experience for your dog, with lots of treats and fuss given after each nail. Training dogs to have their feet handled from puppyhood means they will be less likely to see nail clipping as an issue. If your dog is already scared of having their nails done, you will need to go back to basics and rebuild a positive association. Whatever you do, don’t delay clipping to avoid having to do it! The longer the nail, the longer the quick, and the more likely they are to bleed accidentally.
Dog groomers and veterinary practices will also be able to offer nail clipping services for you if doing it little and often at home is not manageable. Be prepared for this to be something where maybe only a few nails are done at a time, to keep it a stress-free experience.
A note about dew claw removal
Sometimes vets are asked to remove a dog’s dew claws surgically if they are repeatedly getting caught and splitting. Whilst this can be done, there are some important considerations.
Hind dew claws are often very loose and ‘flappy’, attached by little more than skin. Your vet may suggest removing these at the same time as another routine surgery (such as neutering) if you are concerned about them.
Front dew claws are often much more firmly attached by bone, and have a really good blood supply, meaning that removal involves a full amputation through the bone.
In either case, there is not much in the way of extra skin or fat around the area for your vet to close the wound after removal, and wound breakdown after surgery is very common. Dressings are required and it is essential that your dog does not lick the area, as this can cause post-operative infections that take a long time to heal. It is worth balancing these risks against the benefits you would hope to achieve.
Removal of dew claws is considered an act of veterinary surgery, and to be carried out by anyone other than a vet is an illegal mutilation. There is a loophole (sometimes used in working dogs) where the dew claws can be removed by a lay person before a puppy’s eyes have opened, but this is something done without pain relief or anaesthetic and so carries considerable ethical considerations.
Summary
Split nails are a common presentation in dogs, and are often secondary to accidental trauma. Basic first aid and non-emergency treatment by a vet will resolve these quickly. Issues with more than one nail may reflect other systemic disease, and so are worth being checked by a vet. Good levels of exercise, home care and good nutrition are usually adequate to keep nails in good condition and from splitting.
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