Brachycephalic Obstruction Airway Syndrome (BOAS) in flat faced dogs

Dogs with short faces are technically referred to as Brachycephalic (Greek roots; short head) and include Pugs, Boston Terriers, Pekingese, Bulldogs, Shih Tzu.

Dogs bred to have these short faces are compromised in many important ways. The most severely affected breed is generally the English Bulldog.

These dogs make a lot of snorting sounds when breathing due to their face shape.  Most are not affected day-to-day, but they do have limitations which need to be recognised. Some require surgery to correct some of these deformities.

1. Stenotic nares

Narrowed nostrils – their nostrils are often slit like and result in a lot of open-mouth breathing and panting as their nose is effectively partially blocked constantly.  This can be surgically corrected after 5 months of age.

2. Macroglossa

Enlarged tongue – Frenchies and Bulldogs are particularly predisposed to thick and large tongues which contribute to overall obstruction in the mouth.

3. Elongated soft palate

The tissue separating the nasal passage from the oral cavity (mouth) tends to be long and flaps loosely at the back of the throat contributing to the snorting sounds, particularly in English Bulldogs. Excess barking or panting can lead to swelling in the throat which can be problematic.  The soft palate can be surgically trimmed.

4. Tracheal stenosis/Hypoplastic Trachea

The trachea is the windpipe.  The trachea can be very narrow in brachycephalic dogs.  This increases the anaesthetic risk and is a big part of the breathing issues in these dogs.  There is no surgery that can help this issue.

5. Everted Laryngeal Saccules

The normal larynx (space at the back of the throat) has two small pockets called saccules.  When a dog has increased effort in breathing, these will turn inside out (think of the pockets of your jeans popping out).  When this occurs, it obstructs the throat.  This can be corrected surgically and is especially common in Pugs.

Heat, Stress, Excitement, Exercise

Brachycephalic dogs pant inefficiently because they cannot effectively cool their tongues for evaporation. This means these dogs are highly susceptible to life-threatening heat stroke. Maintaining a healthy weight is crucial, as is avoiding exposure to heat, stress, or excessive exercise. We strongly discourage flying with these dogs.

Ideally, brachycephalic dogs should be assessed, and surgery performed if indicated. Brachycephalic Obstructive Airway Syndrome can be progressive and if not corrected at an early stage, can lead to premature death. 

Brachycephalic dogs are also predisposed to other issues of the gastrointestinal tract (vomiting/nausea), multiple types of eye problems, nasal skin fold irritation and infection, allergic skin disease, dental issues and more often need caesarians when breeding.


Brachycephalic dogs show plenty of personality, but they have some complex health issues due to their conformation that owners need to know and plan their lives around.