Unpleasant aromas: Why Does My Pet’s Breath Smell?

Whilst our pets are adorable and lovable, they will occasionally catch us off guard with a lick or a sniff accompanied by an unpleasant smell, but why is that? The most common reasons for your pet to have bad breath are straight forward, for example eating something unsavoury, licking their back end to keep themselves clean, and having dental disease. There are less common causes for bad breath which can be attributed to underlying illnesses so, if you can rule out the most common causes, it may be worth a trip to your local veterinarian to investigate further!

How does dental disease cause bad breath in cats and dogs?

Dental disease is the most common cause of bad smelling breath, or halitosis, in dogs and cats. Dental disease can cause a smell even when present at a low level, however, when allowed to progress it can become increasingly pungent and unpleasant for you to deal with.

The ‘bad breath’ smell can arise from  bacterial build up on teeth, much like the bacteria that builds up on human teeth between brushes. If we neglect to brush our pets’ teeth to remove such bacteria, then a biofilm (a sticky layer which prevents the bacteria from being easily removed when your pet is eating) can form. This biofilm may harbour vast quantities of bacteria as it forms, and over time will calcify to form tartar. This is the hard, yellow-brown material that you may see on your pet’s teeth. Tartar offers bacteria a ‘safe haven’ once it is established. If this stage has occurred, it is then much more difficult to remove. Bacteria inside are unaffected by the actions of eating and tooth brushing if you begin after it has been established.  In addition to harbouring bacteria, the plaque can also provide a source of irritation and infection for the gums, and in extreme cases can cause gum recession or even tooth loss. The combination of large amounts of bacteria and inflammation or infection of the gums forms the bad smell in your pet’s mouth.

Diagram showing how plaque and tartar form on the teeth

How can I prevent my pet from getting dental disease?

The best way to prevent your pet from getting dental diseases is to routinely brush your pet’s teeth, once a day is usually sufficient to prevent a build up of tartar on the teeth. You may be able to find specific dog or cat toothbrushes, and sometimes for smaller pets you can find a finger brush which sits on your finger like thimble (and this should allow you to access most of your pet’s teeth). When brushing your pet’s teeth, the mechanical action of brushing is most important, as this will act to break down the sticky biofilm layer and physically remove some of the bacteria. Some toothbrushes will come with specific cat or dog toothpaste which can also be useful. Although it may not provide much  benefit for your pet’s teeth if it doesn’t stay in contact with them for long, it will certainly make them more compliant with tooth brushing if it tastes nice! It is important not to use human toothpaste with your pets as they often contain chemicals that can be harmful to animals, such as large amounts of sodium, fluoride, or xylitol.

In addition to tooth brushing, there are some supplements which can be useful for managing plaque formation, such as the aptly named ‘plaque-off’, antiseptic pastes or gels which can be applied to the teeth and gums, and some types of food and treats can be useful. There are certain types of kibble and biscuits that are specifically made to be helpful for dental care, and this can be especially useful in cats whose teeth are more difficult to brush. These biscuits are usually larger than normal kibble, quite firm and hard to bite through, making for a crunchy treat that will remove stubborn bits of tartar and provide a slight brushing action on the teeth whilst eating. Other dental treats can also be useful, but you need to think carefully about which types you allow your pet to eat. In order for a dental treat to provide a useful function on the tooth your pet needs to chew it, so if your dog is like mine and eats a dental chew in three bites then it is not likely to be helping much with the teeth! In addition to not necessarily being useful for your pet’s teeth, they may also be quite calorie dense, and so for some pets dental treats may contribute to unwanted weight gain and obesity. A low-calorie alternative for a dental treat for dogs and cats can be raw carrot, some of them may not be fans but I find that lots of them are very happy to eat it! Some people say that bones and antlers are good for maintaining your pet’s dental hygiene, and whilst they do provide the same brushing action on the teeth as other dental treats that are chewed for any length of time, they can also be damaging to the teeth. The main issues you can see with feeding your pets bones or antlers are tooth fractures and injuries to the gums, and if your pet has swallowed any bone fragments then this can be extremely dangerous for their stomach and throat. If you plan to give your pet a bone or antler then make sure you supervise them closely and monitor their mouth for any sign of injury, and also remove any small fragments of bone they may try to ingest.

What should I do if my pet’s teeth already have a lot of tartar?

If it is too late to prevent the tartar from developing then keeping your pet’s teeth clean will become a little more difficult, but the tartar can be removed to allow you to start up a good dental hygiene routine with your pet. The most effective way to remove the tartar from your pet’s teeth, allowing you to start from a clean slate, is to take them to your local veterinarian for a scale and polish procedure. This will involve a general anaesthetic, so may not be appropriate for all pets, however if your local veterinarian agrees then this would be the best way to get your pet’s teeth back to being pearly white. Before you book your pet in for a scale and polish, it would be a good idea to try and train them into the routine of having their teeth brushed, as this is something you will need to keep up after their procedure. The best way to do this is to start slowly, getting them used to having the brush around their face, before using flavoured toothpastes or treats to introduce it into their mouth and moving on to brushing. This can be challenging with some pets, so perseverance is key!

What if my pet’s teeth have lots of infection around them?

If dental tartar has built up on your pet’s teeth and inflammation and infection has formed as a result, then you may start to see further changes to your pet’s mouth. Recession of the gums, loosening of the teeth and infections around the roots of the teeth are all possible complications of dental tartar that has been left for too long. In most of these cases, if the gum is too severely affected or if the tooth has become compromised, then the best option for the tooth is for it to be extracted. If your pet has their dental procedure booked in, or is unable to have a dental procedure due to the anaesthetic risks, then other options to help combat the infection include antibiotics which your local veterinarian may prescribe if appropriate. Antiseptic dental pastes or gels can also be applied to the teeth or gums to reduce the amount of bacteria present. Whilst antibiotics and the pastes or gels will not remove the cause of the infection around the teeth, they will minimise the effects that the infection is having and help improve your pet’s overall oral health.

Why else might my pet’s breath smell?

If there is no obvious dental disease present, or if your pet’s breath is unusually smelly and they are otherwise feeling under the weather, then underlying disease elsewhere in the body may be the cause. The main things that can cause bad breath related to other diseases are problems with blood clotting which can lead to bleeding into the mouth, causing a metallic smell, or problems with the internal organs which can lead to a build up of waste products from the body which can cause ulcerations in the mouth and bad smells because of this, such as with kidney or liver disease. If you are suspicious of any of these then you should have your pet seen by your local veterinarian as soon as possible.