Brachycephalic Obstructive Airway Syndrome (BOAS)
Information for owners of brachycephalic dog breeds.
BOAS affects dogs with a shortened skull structure, which makes them prone to breathing difficulties due to differences in their upper airway anatomy. Severity varies significantly between individual dogs.
Understanding the condition helps you recognise early signs, reduce risks, and seek timely veterinary care.
Which Dogs Are Affected?
BOAS most commonly affects brachycephalic dog breeds, including French Bulldogs, English Bulldogs, Pugs, Boston Terriers, Shih Tzus and Cavalier King Charles Spaniels. Not all dogs within these breeds are affected the same way – some show mild signs, while others experience more significant breathing compromise.
What Causes BOAS?
BOAS results from a combination of anatomical features that restrict airflow through the upper airway:
- Narrow nostrils (stenotic nares)
- A long or thickened soft palate
- A relatively narrow windpipe (trachea)
- Changes to the larynx over time
Together these increase the effort required to breathe – particularly during exercise, excitement, or warm conditions.
Common Signs of BOAS
Dogs with BOAS may show:
- Noisy breathing or snoring
- Snorting, wheezing, or laboured breathing
- Reduced exercise tolerance or tiring easily
- Excessive panting
- Gagging or retching, particularly after activity
- Heat intolerance or collapse in warm weather
Signs may worsen gradually if the condition is not addressed.
Why BOAS Is Important to Address
BOAS is more than just noisy breathing. Ongoing airway restriction can lead to a reduced ability to cope with heat or exercise, episodes of breathing distress, increased anaesthetic risk, and progressive, irreversible narrowing of the airways over time. In more severe cases it can become life-threatening, particularly during hot weather or periods of stress.
Management & Treatment Options
Management depends on how significantly your dog is affected.
How Is BOAS Diagnosed?
Diagnosis begins with a clinical examination and a discussion of your dog’s history and symptoms. Some aspects of the airway can only be properly assessed under light anaesthesia, allowing safe and thorough examination. Your veterinarian may recommend further investigation or referral for specialist assessment depending on the severity of signs.
When Should I Seek Veterinary Advice?
Seek veterinary care if your dog struggles with breathing or exercise, has worsening respiratory noise, pants excessively or shows heat intolerance, or experiences collapse or severe breathing distress. Early assessment improves comfort, safety, and long-term outcomes – if you have any concerns about your dog’s breathing, please contact our team.