Breathing problems in brachycephalic dogs

Long term breathing difficulties and an inability to cool down normally are commonly seen in extreme brachycephalic dogs. This breathing disorder is called ‘Brachycephalic Obstructive Airway Syndrome’, or BOAS, and is a progressive, lifelong disorder that can impair a dog’s ability to exercise, play, eat and sleep. Abnormalities in the airway in brachycephalic dogs include narrowed nostrils and elongation of the soft palate, which obstruct the passage of air through the nose and throat. In some breeds, especially the Bulldog, this may be accompanied by narrowing of the trachea (wind pipe). These abnormalities restrict the airway and reduce the space available for airflow. This makes it difficult for affected dogs to breathe freely and get enough air into their lungs.

Over time, the additional breathing effort that affected dogs take can lead to collapse of the larynx (‘voice box’). In addition to difficulty breathing, restrictions to the flow of air through the nostrils and internal nose structures can make it challenging for brachycephalic dogs to cool down, as the nose is the main area in a dog’s body where heat exchange occurs.

What are the signs my dog may have BOAS?

Dogs with BOAS show an increase in the amount of noise they make when breathing, even at rest, which may sound like snoring, snorting or wheezing. In addition to these breathing sounds, dogs with BOAS often show additional effort when breathing, which may include excessive panting, and laboured and heavy breathing with heaving of the chest and stomach with each breath. Dogs with BOAS are often unable to exercise normally and may have to rest frequently on walks. In severe cases, dogs may show a blue or grey tinge to their gums and tongue (which are signs of low blood oxygen), and may collapse due to lack of oxygen.

In warm weather BOAS signs may become more pronounced and other signs of overheating (‘heatstroke’) may occur including heavy panting, elevated body temperature, glazed eyes, increased pulse, vomiting/diarrhoea, excessive thirst, dark red tongue, excessive drooling and staggering. Overheating can be life threatening, and dogs may seizure, collapse, become unconscious, and in some cases may sadly die.

Dogs with BOAS may find it difficult to sleep normally, often snoring while sleeping and sometimes waking up due to brief periods where their breathing stops. Dogs with BOAS may try to prop their head up while they are asleep to keep their airway open. Some dogs with BOAS may also show problems with their gastrointestinal system, signs of which may include regurgitation, vomiting and coughing up foamy saliva. The signs of BOAS are progressive and often worsen over time. In severe cases, signs of BOAS may be severe by 12 months of age.

What should I do if my dog shows signs of BOAS?

If your dog shows any of the above signs, you should seek veterinary advice immediately. If you own a French Bulldog, Pug or Bulldog then you can have your dog graded as part of the Kennel Club and University of Cambridge Respiratory Function Grading Scheme. This scheme assesses your dog for BOAS and can help you determine how severe it may be.

Treatment options for dogs that are affected are available that aim to reduce the amount of obstruction to your dog’s airway and improve their breathing abilities. Early intervention is often recommended as this may prevent or slow further progression of signs. Your vet will take a history of your dog’s clinical signs, and will assess the degree of respiratory compromise in your dog – this may include a ‘walk test’ to see how they cope with a short amount of exercise, and visual inspection of your dog’s nostrils. 

If your vet suspects your dog has BOAS, they may recommend that your dog’s airways are assessed under general anaesthetic, where their nose and throat can be fully visualised. If abnormalities are seen, for example, their soft palate is overly long and/or thick and obstructing their airway, their larynx is showing signs of collapse or their nostrils are significantly narrowed, your vet may recommend surgery. Surgery may include opening up their nostrils, trimming away their excessive soft palate, and removing collapsed parts of the larynx. Some specialists may offer advanced laser surgery to reduce further obstruction inside your dog’s nose (behind their nostrils), where present.

Surgery helps many dogs with brachycephaly enjoy a better quality of life, but owners should be aware that their dog will not be ‘normal’ even after surgery, and precautions should still be taken to avoid exacerbating airway problems in their dog. This includes keeping your dog lean, as obesity exacerbates breathing problems; avoiding taking your dog out in hot weather; taking your dog on regular short walks to avoid putting stress on their airways while maintaining fitness; and using a harness instead of a collar to avoid putting pressure on their airway.

*Summer warning* Brachycephalic dogs are at high risk of overheating in warm weather, even in the UK. If you notice any signs of overheating in your dog described above, immediate action should be taken while contacting your vet for further evaluation. Steps should include moving your dog to a cool, shaded place, soaking your dog with cold water to cool down, and providing them with a small amount of water to drink to rehydrate.


Obesity is prevalent in the general canine population, affecting an estimated 20-40% of dogs. Many dogs with BOAS are overweight or obese, which may in part be due to their reduced ability to exercise normally. This is problematic as a high body condition score is a risk factor for BOAS, and is associated with an increased severity of clinical signs. To assess your dog’s body condition score, you can use visual scoring guides such as one developed by the World Small Animal Veterinary Association here, and discuss any concerns with your vet.

Owners should aim to keep their brachycephalic dogs lean to avoid exacerbating clinical signs. This may include restricting the number of treats you give your dog, feeding your dog specifically formulated obesity diets, and maintaining regular exercise. Further information is available on the Dog Obesity article and in the Kennel Club’s ‘Managing your dog’s weight’ guide here.

Who can I contact for further advice?

The Kennel Club is not a veterinary organisation and is unable to provide general or case specific veterinary advice.  If you have any questions regarding any of the issues discussed in this article then please contact your local veterinary practice for further information.

This article was written by Dr Rowena Packer from the Royal Veterinary College who has given the Kennel Club kind permission to replicate this article.   Dr Rowena Packer is a Research Fellow at the Royal Veterinary College. Her research interests include many areas of canine inherited disease including brachycephalic health and canine epilepsy.

Further resources and information

Respiratory Function Grading Scheme

The Kennel Club and University of Cambridge Respiratory Function Grading Scheme helps breeders of French Bulldogs, Pugs and Bulldogs lower the risk of producing puppies affected by breathing problems.

Film: Dog health – What is Brachycephalic Obstruction Airway Syndrome?

In this learning resource, BOAS experts Dr Sargan, Dr Liu and Dr Ladlow from the University of Cambridge will ensure viewers are provided with information as to what Brachycephalic Obstructive Airway Syndrome is, how it affects brachycephalic breed (short-nosed dogs e.g. Pugs/Bulldogs/French Bulldogs) and the signs and symptoms owners/potential owners should be aware of.

Buying a flat-faced dog

If your thinking of buying a flat-faced puppy, such as a French Bulldog, Pug or Bulldog, it's important that you find out about the health and welfare issues that impact some of these dogs.

What the Kennel Club are doing to improve brachycephalic health

Improving the health of brachycephalic dog breeds and any other breed with health concerns is the Kennel Club’s top priority. We are a not for profit organisation and have invested almost four million pounds in the last decade into research that will help to improve dog health.

Current research: Cambridge BOAS research Group

The Kennel Club Charitable Trust is funding ground breaking research into Brachycephalic Obstructive Airway Syndrome (BOAS) at Cambridge University. The aim is to improve the health of dogs which are already affected by BOAS and to create breeding tools that will help breeders make informed choices and ultimately breed healthier puppies.

Specialist clinic for short muzzled dogs

The RVC has the only specialist clinic in UK for brachycephalic dog breeds, also known as short-muzzled or short-nosed dogs. Brachycephalic dogs can suffer from long-term health problems that affect their breathing, eyes, bones and gait, heart, skin and ears.


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