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Brachycephalic Dog Breeds – Flat-Faced Breed List, Risks, BOAS & FAQs

↯ Key takeaway points

  • Brachycephalic dog breeds have short snouts and are extremely popular today.
  • Brachycephalic obstructive airway syndrome (BOAS) is a respiratory disorder in dog breeds with short muzzles and skulls.
  • Dogs with BOAS experience symptoms such as noisy breathing, intolerance to heat and exercise, sleep apnea, and gastrointestinal problems.
  • BOAS can lead to longer recovery times after exercise, fainting, and more severe cases can result in cyanosis, collapse, and death.
  • Brachycephalic dog breeds are popular in the USA, with French Bulldogs and Bulldogs ranking in the top 10 most popular breeds.
Written by Jay
BsC (Hons) Animal Behaviour & Welfare graduate with a passion for advocating for misunderstood animals.
Zoo and wildlife doctor in veterinary medicine passionate about animal welfare and preventive medicine.
Published on
Wednesday 3 March 2021
Last updated on
Friday 7 July 2023
brachycephalic dog breeds
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Brachycephalic Obstructive Airway Syndrome (BOAS)

Brachycephalic obstructive airway syndrome (BOAS) is a respiratory condition found in dogs with short muzzles and skulls. Due to selective breeding for extreme brachycephaly, these dogs may have deformities in their upper airway tract, as the soft tissues have not reduced enough in proportion to the length of their skull.

BOAS causes specific symptoms, such as noisy and labored breathing, intolerance to heat and exercise, sleep apnea, vomiting, and regurgitation. Dogs with BOAS may also faint due to their inability to breathe freely and take longer to recover from intense exercise. More severely affected dogs may sleep with a toy between their teeth or sleep upright to keep their airways open. Unfortunately, in some cases, BOAS can lead to cyanosis, collapse, and even death.

One study suggests that over half of the owners of brachycephalic breeds are unaware that their dog has BOAS, assuming their dog’s breathing is normal for their breed. As a responsible owner, it is crucial to be aware of the signs of BOAS to ensure your furry friend receives proper treatment.

In summary, BOAS is a respiratory disorder caused by selective breeding for short muzzles and skulls. It can lead to severe symptoms that worsen over time, causing discomfort, fainting, and even death in some cases. Being aware of the signs and seeking treatment is crucial for your dog’s health and well-being.

Symptoms of BOAS

BOAS causes distinct symptoms like noisy, labored breathing, heat and exercise intolerance, sleep apnea, and gastrointestinal problems such as vomiting and regurgitation. Also, dogs with BOAS take longer to recover from intense exercise and sometimes faint due to their inability to breathe freely. Also, more severely affected dogs may sleep with a toy between their teeth to keep their mouth open for easier breathing or sleep upright to keep their airways open. In the worst cases, BOAS leads to cyanosis, collapse, and death, according to one study. Symptoms of BOAS progress with age and become severe by 12 months, according to another study.

One study suggests that over half of owners of brachycephalic dog breeds do not recognize that their dog has BOAS, instead citing that their dog has “normal breathing for the breed.” As a responsible owner, you must be aware of the signs of BOAS to ensure that your dog gets the treatment it needs.

Brachycephalic dog breeds are some of the most popular breeds in the USA. In 2017, the AKC listed French Bulldogs and Bulldogs in the top 10 most popular breeds. A further seven brachycephalic breeds are in the top 31 most popular breeds.


The Boxer is a medium to large breed from Germany. Their suspicion of strangers and hard-working disposition makes these dogs adept at working and competing in dog sports. Boxers successfully work as service dogs as well as police dogs and herding dogs. However, Boxers are also prone to health problems that affect their quality of life and working ability. These health issues include cancer, heart conditions, hypothyroidism, hip dysplasia, epilepsy, and entropion. The Boxer’s breed standard encourages breeding for a shorter muzzle, specifying that the length of the muzzle to the head should be a ratio of 1:3.


Bulldogs are a medium brachycephalic dog breed from England. This is a very distinctive breed, with a muscular and hefty build and a pushed-in nose. Originally bred for bull-baiting, Bulldogs went on to become popular family pets and became the fifth most popular breed in the USA by 2017. Today, the breed suffers a range of health problems. Among the most common are hip dysplasia, patellar luxation, interdigital cysts, cherry eye, and allergies. But perhaps most importantly, the Bulldog’s brachycephalic skull makes it prone to airway obstructive syndrome. Bulldogs often have small nasal cavities which also makes them very prone to overheating, heavy breathing, and snoring. Bulldog owners may keep these problems under control if they avoid situations that are unsafe for their dogs.

bulldogs are brachycephalic
Bulldogs are brachycephalic dogs!

Boston Terrier

Boston Terriers are small and compact dogs from the USA. These distinctive dogs are known for being happy-go-lucky with a good sense of humor. They are also eager to please and highly trainable. While originally bred for fighting and ratting, Boston Terriers became popular family pets with their outgoing attitudes and protective tendencies. Today, Boston Terriers struggle with corneal ulcers, cherry eye, deafness, and heart murmurs.


The Pug is a popular brachycephalic dog breed that was first bred in China. The breed retains its affectionate devotion towards its owners and its charming personality. Today, Pugs struggle with a wide range of health issues attributed to their conformation. These include scratched corneas, eye prolapse, and painful entropion because of their prominent brow ridges. Hip dysplasia affects nearly 64% of Pugs according to the OFA. Lastly, they are also susceptible to demodectic mange due to a genetic vulnerability to the Demodex mite.

Shih Tzu

The Shih Tzu is a companion breed hailing from Tibet. Originally favorites of Chinese royalty, Shih Tzus have been popular family pets with their affectionate nature and friendly personality. Like other toy breeds, Shih Tzus are prone to health issues, some of them hereditary. These include hypothyroidism, intervertebral disk disease, portosystemic shunt, and hip dysplasia. They are also susceptible to respiratory problems due to their brachycephalic structure, including brachycephalic airway obstructive syndrome.


Chihuahuas are thought to descend from the Techichi, a small dog breed from the Toltec civilization of Mexico. Today, Chihuahuas retain their fierce loyalty to one person and their preference for being with other Chihuahuas. Not all Chihuahuas are brachycephalic – while the deer head variety has a longer nose, the apple head variety has a rounder head and shorter nose. Only apple head Chihuahuas are acceptable in AKC conformation shows. This conformation puts Chihuahuas at risk of developing soft spots on the skull. They are also susceptible to hydrocephalus, collapsed trachea, heart disorders, and luxating patella.

Chihuahuas are considered brachycephalic dogs.

Chow Chow

Chow Chows are a basal breed originating from northern China. With origins as a war dog and sled dog, the Chow Chow is known for its discernment of strangers and the protectiveness of its family. Unfortunately, Chow Chows are a high-risk breed for autoimmune diseases and have a predisposition for skin cancer. They also suffer from entropion, cataracts, lymphoma, hip dysplasia, diabetes, and glaucoma.


The Pekingese is a toy breed from China. This unique breed was favored by the royalty of the Chinese Imperial court, where it gained fame as a companion and lap dog. Because of its characteristics, the Pekingese is sometimes part of the development of designer crossbreed. These include the Peekapoo and the Peke-a-tese. Like other toy breeds, the Pekingese is prone to congestive heart failure, heart murmurs, skin allergies, eye ulcers, and progressive retinal atrophy. Their long backs can also make them vulnerable to spinal injuries. Lastly, their flat faces make them unsuitable for intense exercise, and they only need 30 minutes per day.

Lhasa Apso

The Lhasa Apso is a small breed originating from Tibet. It was originally bred to be an interior sentinel in Buddhist monasteries, while the Tibetan Mastiff stood guard outside. Lhasa Apsos are known for being loyal and eager to please but suspicious of strangers. Unlike some breeds on our list, Lhasa Apsos are generally healthy dogs but are prone to sebaceous adenitis and progressive retinal atrophy. They also occasionally develop cherry eye due to being a brachycephalic breed.

the lhasa apso
Lhasa Apsos originated from Tibet.


Bullmastiffs are large-sized dogs originating from Britain. This breed was popular in the 19th century as a guard dog for gamekeepers. At this time the preferred color for the breed was brindle as it worked as effective camouflage, particularly at night. Today, the Bullmastiff is less commonly used as a guardian, now finding favor as a family dog. Health concerns with the modern breed include hip dysplasia, elbow dysplasia, entropion, lymphoma, progressive retinal atrophy, and osteoarthritis. Compared to other breeds on this list, Bullmastiffs do not struggle as much with their brachycephalic conformation. This is because this breed has a longer nose than others, so much so that some breeders argue that Bullmastiffs are not brachycephalic.

English Toy Spaniels

Also known as the King Charles Spaniel, the English Toy Spaniel is a small breed that may have originated from East Asia. Historically the breeds that make up the English Toy Spaniel were hunting dogs, but this breed was not well-suited for hunting due to its stature. It retains its hunting instincts but is better suited as a lap dog because of its stature and health issues. English Toy Spaniels are prone to a range of eye problems including cataracts, microphthalmia, keratitis, and distichia. They are also prone to heart conditions such as mitral valve disease and patent ductus arteriosus, both of which are inheritable. According to an OFA study of 105 breeds, this breed was the 7th worst for cardiac disease.

Serious Health Concerns in Brachycephalic Dog Breeds

BOAS is a serious welfare issue in dogs because of its distressing symptoms. Affected dogs may have stenotic nares, elongated soft palate, hypoplastic trachea, everted laryngeal saccules, and problems with the eyes and teeth.

Stenotic Nares

Stenosis describes the abnormal narrowing of a structure in the body. If a dog has stenotic nares, it means that their nostrils are too narrow for them to breathe efficiently. So, dogs with severely stenotic nares may switch from nasal breathing to oral breathing with very gentle exercise or moderate stress. So, stenotic nares are a reliable indicator of BOAS in a brachycephalic dog. Surgery can be done to widen the nostrils of a brachycephalic dog.

Elongated Soft Palate

Dogs with severe BOAS have significantly thicker soft palates compared to minimal cases, according to a 2011 study. Not only this, but the soft palate’s length causes the low-frequency snoring sound that dogs with BOAS make. So, dogs with BOAS may inhale the elongated soft palate into the larynx, states a 2015 study. If the soft palate hangs down into the airway it can easily block the trachea. When severe, this problem can cause complete obstruction of airflow. Dogs with an elongated soft palate may require surgery to remove the excess tissue.

Hypoplastic Trachea

If your dog has a hypoplastic trachea it means that their tracheal cartilage rings are malformed. Because of this malformation, some dogs develop aspiration pneumonia, which adds further risk to their health. Unlike other complications of BOAS, there is no specific treatment for tracheal hypoplasia. Some brachycephalic dogs’ tracheal hypoplasia improves or completely resolves with maturity.

Everted Laryngeal Saccules

Laryngeal saccules are the air sacs that are found between the vocal folds and the laryngeal wall. So, when dogs with BOAS are unable to breathe properly, they must work harder to fill their lungs with air. This causes the laryngeal saccules to pull down into the airway, blocking the opening of the trachea. Your vet may recommend completely removing the laryngeal saccules if they affect your dog’s breathing.

Heat Stroke

Heat stroke is a serious complication of BOAS in many dogs. Because dogs with BOAS pant inefficiently they struggle to cool down in hot weather and during exercise. Plus, according to VCA Hospitals, the English Bulldog is the most susceptible breed to heat stroke as a result of its brachycephalic stature. Brachycephalic breeds should not exercise in warm weather to prevent heat stress and heat stroke.

Eyes and Eyelids

Many brachycephalic dog breeds are prone to eye problems. Often, their eyelid opening is excessively wide, and their eyelids can turn inwards (entropion) or outwards (ectropion). So, this leads to drying of the cornea or damage to the cornea as a result of contact with the eyelashes.


Brachycephalic breeds may be more prone to dental health issues than other breeds. When the jaw shortens, as is the case for a brachycephalic dog, the teeth have less room to grow. The brachycephalic dog grows the same number of teeth, which grow in crowded. This makes it difficult to clean the teeth, leading to tooth decay.

brachycephalic dental health
Brachycephalic dogs are prone to dental health issues.

Birthing Problems

Anecdotally brachycephalic dogs are most likely to need a C-section. This is because of the difference in size between the pelvic canal of the mother and the size of the puppies’ heads. This results in a physical blockage to delivery. According to research, 92.3% of Boston Terriers, 86.1% of Bulldogs, and 81.3% of French Bulldogs require C-sections.

Skin Issues in Brachycephalic Dog Breeds

Brachycephalic dog breeds with excessive wrinkles may be prone to skin conditions. This is because their deep skin folds retain moisture, making them an ideal breeding ground for yeast and bacteria. Also, local infections within the skin folds are common without regular cleaning. In long-term infection cases, the skin can become thicker and darker in color.

Living with Brachycephalic Dog Breeds

One of the most important steps to take when owning a brachycephalic dog is to use a dog harness rather than a collar. A collar adds strain to the compromised airways of brachycephalic breeds. So, by using a harness instead, you can walk your dog without adding extra pressure on your dog’s breathing.

Unlike other dog breeds, brachycephalic breeds benefit from shorter walks and low-impact exercise rather than long, intense walks. The English Bulldog, for example, benefits from 30 minutes of exercise per day, with any more than 40 becoming dangerous for them. In line with this, the risk of obesity for brachycephalic breeds is higher, so monitor their weight closely.

Treatment of Brachycephalic Dog Breeds with Breathing Difficulty

Do not delay treatment if your dog shows signs of BOAS. Not only can BOAS progress and become worse, but it can also lead to collapse and death if not addressed by a vet.


The full physical examination for BOAS might include an examination of the throat under general anesthesia. Furthermore, a CT scan of the head may be done to look at the conformation of the soft palate and the nasal cavities. Also, the nasal cavities are sometimes evaluated through endoscopy. Lastly, a CT scan or X-ray of the chest and abdomen may be done to check for secondary problems like aspiration pneumonia.


The main focus of BOAS treatment is to unblock the airways. This can be done by surgically widening the nostrils, shortening the soft palate, and removing the laryngeal saccules. These surgical procedures usually go well for dogs and most recover enough to never need any more treatments for their BOAS. However, some dogs continue to decline in health afterward.

Should you Buy Brachycephalic Dog Breeds?

Responsible brachycephalic dog breeders will aim to improve the breed rather than selecting for extreme brachycephalic traits. Ask the breeder how they are working to improve their breed. Examples of work being done include selecting for a longer nose or only breeding from dogs with wider nostrils. The UK Kennel Club runs the Respiratory Function Grading Scheme which suggests that owners of brachycephalic dogs should test their dogs every 2 years for their lifetime. This scheme awards a grade to your dog. All severely affected dogs should not breed.

The UK Kennel Club also employs the Breed Watch scheme. Breed Watch provides information as an “early warning system” to judges so that they can identify breed problems. Such problems include nose and nostrils, body condition, and skin and wrinkling.

The short answer – brachycephalic dog breeders must continue to work to improve their breed, and supporting those that do the work is important. Make sure that you ask the breeder about the health of the parents. Ask to see their health testing certificates as proof that the breeder carries out health testing.

brachycephalic dog breed
Brachycephalic dog breeders should always aim to improve the breed.

Brachycephalic Dog Breeds – FAQs

Have any more questions or concerns about brachycephalic dog breeds? Feel free to refer to our Frequently Asked Questions section for more details. If in doubt about your dog’s health, always ask your vet for advice.

What breeds are brachycephalic?

There are many brachycephalic dog breeds, meaning that these breeds have a short nose and flat face. These dog breeds include the Affenpinscher, American Bulldog, Boxer, Boston Terrier, Bulldog, Bullmastiff, Cane Corso, Chihuahua (apple-headed), Chow Chow, Dogue de Bordeaux, English Mastiff, French Bulldog, Griffon Bruxellois, Japanese Chin, Lhasa Apso, Pekingese, Pug, Rottweiler, and the Shih Tzu. Mixes of these breeds are also often brachycephalic. Such mixes include the Chug (Chihuahua and Pug) and the Bulloxer (Bulldog and Boxer). Not all mixes from brachycephalic breeds are brachycephalic, however, which can be seen in mixes like the Jack Chi (Jack Russel and Chihuahua) or the Chiweenie (Chihuahua and Dachshund).

What are the symptoms of brachycephalic airway obstructive syndrome?

Brachycephalic obstructive airway syndrome (BOAS) causes several symptoms. These include noisy breathing, heat intolerance, exercise intolerance, sleep apnea, vomiting, and regurgitation. In severe cases of BOAS, the affected dog may develop cyanosis, collapse, and ultimately die. The symptoms of BOAS progress with age and surgery may be needed to relieve respiratory distress. Symptoms are often aggravated by eating, drinking, exercising, and stress.

How do you treat brachycephalic dogs?

Brachycephalic dog breeds sometimes need surgery to help them to breathe more easily. This surgery includes widening the nostrils, removing the laryngeal saccules, and shortening the soft palate. Most dogs recover well from these surgeries and do not require any more surgery after the procedures are done. Management of brachycephalic dogs at home involves restricting their exercise, using harnesses instead of collars, and monitoring their skincare closely. Your brachycephalic pup still needs exercise and mental stimulation, so low-impact exercise is essential for their mental and physical health. Puzzle toys are also an essential part of your pup’s care as they are a low-impact way to stimulate your dog mentally.

Can brachycephalic dogs fly?

Some airlines ban brachycephalic dogs from traveling with them, including United Airlines, Delta Airlines, and American Airlines. Airlines where brachycephalic dogs are not outright banned usually have strict restrictions regarding the travel of these dog breeds. This is because brachycephalic breeds are known to struggle with flying. This is because these breeds may struggle to cope with the stress of flight, which causes heavy panting and respiratory distress. In July 2010, statistics were released by the US Department of Transportation that showed that half of the 122 dog deaths in the last five years were brachycephalic breeds. 25 of the 122 dogs were English Bulldogs and 11 were Pugs.

Do all Bulldogs have breathing problems?

All English Bulldogs are prone to breathing problems, but the severity of these problems varies from one dog to another. While one Bulldog may be able to breathe well enough to confidently compete in agility, another may struggle to go on a walk around the block without heavy panting. While one breeder may prefer to selectively breed for new and unusual colors in the Bulldog, another may focus on breeding to tackle the problems with the breed. Responsible Bulldog breeders will aim to breed dogs with wider nostrils and overall better breathing ability. As such, puppy buyers have the power to help to turn the tides for Bulldogs. When visiting a Bulldog breeder, always ask what they are doing to improve the health of their breed.

Why do brachycephalic dogs overheat?

Brachycephalic dogs must work harder than their long-snouted counterparts to reduce their temperature through heavy panting. Panting reduces a dog’s body temperature, and because a brachycephalic dog must pant harder to get enough air, their temperature stays higher for longer. The longer soft palate and laryngeal saccules may even block the airway with each inhalation, making breathing more difficult for the dog. This leads to respiratory distress and overheating. When a brachycephalic dog overheats, they do not have the ability to cool down fast enough and become vulnerable to heat stroke. Without emergency treatment, a dog with heat stroke can collapse, lose consciousness, and die. Brachycephalic breeds like the English Bulldog should not exercise in hot weather because of the risk of heat stroke.

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