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Brachycephalic Obstructive Airway Syndrome (BOAS)

Published on 28 Apr 2021

English Mastiff dog in green summer grass.

Difficulty breathing is a distressing consequence of the popularity of brachycephalic (short faced) breeds of dog.

What is Brachycephalic Obstructive Airway Syndrome (BOAS)?

Brachycephalic Obstructive Airway Syndrome refers to a condition affecting brachycephalic (short nosed) dogs and cats. 

The shape of their nose, face and upper airways makes it more difficult for them to breath. Their short noses mean that the upper airways are condensed, however some of the tissues, such as the soft palate, are not condensed. Airflow is obstructed by these tissues. Over time the problem worsens, and secondary changes occur to the airway as a result of the chronic inflammation and pressure on the body. 

Abnormalities to the airway in brachycephalic obstructive airway syndrome include: 

  • Stenotic nares (narrow nostrils)
  • Extended nasopharyngeal turbinates (bony ridges that help to humidify air that can cause airflow obstruction when they are too long) 
  • Elongated soft palate 
  • Laryngeal collapse 
  • Hypoplastic trachea (a narrow windpipe)
  • Everted laryngeal saccules (tissues that usually sit in front of the vocal cords become pulled into the windpipe due to the increased pressure on the airway, causing further blockage of the windpipe). 

Secondary problems also include hiatal hernia, where the stomach passes into the chest from the abdomen as the pressure from the abnormal airways acts to suck the stomach through the diaphragm. 

Which pets are most affected?

The standout breed affected by Brachycephalic Obstructive Airway Syndrome is the French bulldog, followed closely by British bulldogs and Pugs. 

The ten breeds of dogs with the highest prevalence of Brachycephalic Obstructive Airway Syndrome in 2020 according to PetSure data was: 

Breed Prevalence
French bulldog7.20%
British bulldog5.41%
Boston Terrier2.98%
Australian bulldog2.81%
Exotic Shorthair0.75%
Cavalier King Charles Spaniel0.57%
Tibetan Spaniel0.36%

Source: PetSure, 2020. Prevalence = Total number of unique claiming pets / total number of insured pets across 12-month period. Excludes breeds with less than 500 active pet insurance policies.

Signs of Brachycephalic Obstructive Airway Syndrome 

Snoring or noisy breathing is often one of the first signs that a dog has obstructed airways. While it might sound funny the sound is caused by tissues preventing air from easily flowing into the airways, and subsequently into the lungs. 

Noisy breathing is not normal and is a sign of a problem. Ongoing signs can include a reluctance to exercise or difficulty exercising, vomiting or regurgitating, collapse, coughing or gagging and heat stroke. These are all signs that something is seriously wrong, so if your dog experiences these signs, seek veterinary attention immediately. 

Diagnosing Brachycephalic Obstructive Airway Syndrome

While a presumptive diagnosis can be made based on breed and history, usually a general anaesthetic is needed to perform a thorough airway examination to assess the severity of the problem. Stenotic nares are more easily diagnosed as these can be seen just by looking at the dog.  

Management of Brachycephalic Obstructive Airway Syndrome 

Management in young dogs is typically focussed on attempting to open the airways as much as possible. The aim is to prevent the secondary changes to the airways and improve quality of life by increasing the patient’s airflow. This may involve shortening the elongated soft palate, widening the nostrils and addressing any other changes noted while under anaesthetic such as everted saccules. 

In older dogs, or more severe cases intensive care may be needed to stabilise the patient and perform airway surgery. Some dogs need to have a tracheostomy, meaning an opening in the neck for them to breath through. For some this may be temporary but other dogs may require it for life. 

Surgical correction for other secondary conditions such as hiatal hernia may also be required. 

If you are concerned that your pet might have BOAS, get in touch with your vet for advice.

How much does it cost to treat?

According to PetSure claims data in the 2020 calendar year, the average, single treatment cost relating to Brachycephalic Obstructive Airway Syndrome was $893 with the highest, single treatment cost being $14,916.  

Disclaimer: Reimbursement for these claims would be subject to limits, such as annual benefit limits or sub-limits, benefit percentage, applicable waiting periods and any applicable excess. Cover is subject to the policy terms and conditions. You should consider the relevant Product Disclosure Statement or policy wording available from the relevant provider. 


  1. Nelson, R & Couto, 2003, Small animal internal medicine, 3rd edition, Mosby, USA. 
  2. Williams, Krista., Yuill, C., VCA Hospitals, Brachycephalic Airway Syndrome in Dogs, accessed on 24/11/20

Terms, conditions, waiting periods, limits and exclusions apply. is issued by The Hollard Insurance Company Pty Ltd ABN 78 090 584 473, AFSL 241436, is arranged and administered by PetSure (Australia) Pty Ltd ABN 95 075 949 923, AFSL 420183 (PetSure) and is promoted and distributed by PetSure’s Authorised Representatives (AR) Pet Insurance Pty Ltd ABN 38 607 160 930, AR 1234944 and Pet Culture Pty Ltd ABN 69 644 613 098, AR 001284860. Any advice provided is general only and does not take into account your individual objectives, financial situation or needs. Please consider the Product Disclosure Statement (PDS) to ensure this product meets your needs before purchasing. PDS and Target Market Determination available at .


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Kylie Mitchell

Kylie Mitchell


Kylie Mitchell is a veterinarian with over 17 years experience in animal health and welfare, including in the veterinary and pet insurance industries

She has three rescue cats (Noah, Bei Bei and Meeka), four very old cockatiels and a pond-full of fish.

Kylie Mitchell's Pets

  • MeekaMeeka
  • Bei BeiBei Bei
  • NoahNoah

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