강아지 단두종 기도 증후군(BOAS) 증상과 원인, 진단·치료와 관리 포인트 총정리

Brachycephalic Obstructive Airway Syndrome (BOAS) in Dogs: Symptoms, Causes, Diagnosis, Treatment, and Management Essentials

RespiratoryDiseasesMeongsiljang Veterinary Advisory Board

Brachycephalic Obstructive Airway Syndrome (BOAS) is a condition that causes breathing difficulties in brachycephalic dog breeds due to abnormal airway structures. Early diagnosis and proper management are essential.

What is Brachycephalic Obstructive Airway Syndrome (BOAS) in Dogs?

An anatomical illustration showing the abnormal airway structure in brachycephalic dog breeds

Brachycephalic Obstructive Airway Syndrome (BOAS) is a congenital condition in brachycephalic dog breeds where abnormally narrowed airway structures make breathing difficult. It is a multi-organ syndrome resulting from the combined effects of abnormalities in several structures, including the nostrils, nasal septum, larynx, and trachea. The short nose and flat facial structure impede airflow, leading to insufficient oxygen supply. As the condition progresses, symptoms such as exercise-induced respiratory distress, coughing, and signs of oxygen deprivation may appear. Early diagnosis and appropriate management are key to determining survival rates and quality of life. Therefore, creating a healthy living environment tailored to the breed’s characteristics is essential.

What are the Main Causes of BOAS?

Brachycephalic Obstructive Airway Syndrome (BOAS) is primarily caused by genetic factors and selective breeding. In brachycephalic breeds, repeated selective breeding to maintain their short snouts and flat faces has led to abnormal development of the airway structures. This results in narrowed nostrils, weak cartilage that fails to properly support the airways, causing them to collapse, and excess soft tissue at the back of the throat that obstructs the airway. These structural abnormalities work together to severely impair breathing.

An explanation comparing the facial structure and airway abnormalities of brachycephalic breeds.

What are the Main Symptoms of BOAS?

Brachycephalic Obstructive Airway Syndrome (BOAS) in dogs presents with a variety of symptoms, primarily centered around breathing difficulties. As the condition worsens, it can significantly hinder daily activities. The main symptoms include:

Breathing difficulties: Rapid breathing, panting, or noisy breathing through the nose.

Coughing or snoring: Sounds caused by narrowed airways restricting airflow.

Signs of oxygen deprivation: Bluish discoloration of the face or risk of fainting.

Excessive fatigue after exercise: Difficulty even with short walks and needing longer rest periods.

Breathing issues during meals: Choking or difficulty swallowing while eating.

A brachycephalic puppy showing signs of breathing difficulty

Symptoms Requiring Immediate Veterinary Attention

If your dog suddenly has difficulty breathing, has blue gums, faints, or has severe difficulty swallowing, consult a veterinarian immediately. These are signs of acute respiratory distress that can be life-threatening. Be especially cautious if these symptoms occur during the summer or after exercise.

How is BOAS Diagnosed?

BOAS is diagnosed through clinical signs, imaging studies, and endoscopic examinations. The veterinarian directly listens to the dog's breathing patterns and airway sounds, and evaluates the structure of the nostrils and throat. Imaging tests, such as chest X-rays or CT scans, help identify structural abnormalities in the airways, while endoscopic examinations accurately assess the position of soft tissues and the degree of airway narrowing. Through this process, the severity of the condition is evaluated, and the treatment plan is determined.

A veterinarian examines the airway of a brachycephalic puppy using an endoscope.

What are the Treatment Options for BOAS?

Treatment for Brachycephalic Obstructive Airway Syndrome (BOAS) depends on the severity of symptoms. Mild cases can be managed through lifestyle adjustments, while moderate to severe cases require surgery. The main treatment options are as follows:

Nasal Stenosis Correction: If narrowed nostrils restrict airflow, a surgical procedure to widen them can provide relief.

Soft Tissue Resection: This involves removing the elongated soft tissue at the back of the throat to clear the airway.

Airway Support Surgery: In cases where the airway collapses, an artificial stent is inserted to keep it open.

Weight Management: Excess weight increases respiratory strain, so maintaining a healthy weight is essential. Consistent weight control remains important even after surgery.

A veterinary team performing airway surgery on a brachycephalic puppy

BOAS Management Tips at Home

Consistent care remains essential even after surgery. To enhance your dog’s quality of life, please follow these care guidelines:

Air Quality Management: Regularly purify indoor air and avoid exposure to smoke or strong odors.

Temperature Control: Avoid going outdoors during hot weather or in high-temperature environments, and maintain an appropriate indoor temperature.

Walk Schedule Adjustment: We recommend short, frequent walks and advise against excessive exercise.

Feeding Method Improvement: Use slow-feed bowls or devices designed to encourage slower eating.

Regular Check-ups: Have your veterinarian regularly monitor your dog’s respiratory condition.

A brachycephalic puppy eating from a slow-feed bowl.

Breed-Specific Precautions and Prevention of Recurrence

Brachycephalic breeds such as English and French Bulldogs, Pugs, Pekingese, Shih Tzus, and Boston Terriers are at a higher risk of developing Brachycephalic Obstructive Airway Syndrome (BOAS). In particular, selecting breeding pairs without considering airway anatomy can exacerbate the condition. It is important to consult with a veterinarian before planning any breeding. Additionally, consistent environmental management and weight control remain essential even after surgery.

Reviewed by a veterinarian

Dr. Tony — Punnawat Phongkittirak

Veterinarian

A veterinarian who majored in veterinary medicine at Khon Kaen University, Thailand, and completed the IVSA program at North Carolina State University in the United States. Drawing on clinical experience at animal hospitals, he works in the pet healthcare field and is dedicated to building a digital care environment that connects pet parents with veterinarians.

Frequently Asked Questions

Can BOAS be completely cured?

Surgery can significantly improve symptoms, but it doesn’t completely change the congenital structure of the airway. Therefore, ongoing care is necessary.

Which breeds are more susceptible to BOAS?

Brachycephalic breeds such as English Bulldogs, French Bulldogs, Pugs, Boston Terriers, Pekingese, and Shih Tzus are at particularly high risk. Among these, English Bulldogs, Pugs, and Boston Terriers are reported to be affected more frequently.

How long does the recovery period after surgery take?

The post-operative recovery period varies depending on the individual patient, surgical technique, and severity of the condition, making pre- and post-operative care essential. While pets can typically resume some daily activities within 1 to 2 weeks, full recovery may take several months.

Can dogs with BOAS go for walks?

It’s possible, but keep walks short and frequent, and avoid them in hot weather or high-temperature environments. If your pet shows signs of breathing difficulty during a walk, stop immediately and let them rest.

Is BOAS hereditary?

Yes, BOAS is largely influenced by genetic factors and is closely linked to the characteristics of brachycephalic breeds. Therefore, it is important to consider genetic factors when breeding.

Comparison Table of BOAS Treatment Methods

Item	Effectiveness Level	Recovery Period	Precautions
Nostril widening surgery	High	Can resume within 1–2 weeks	Walk restriction required
Soft tissue resection surgery	Very high	Possible to resume within 2–3 weeks	Be careful with food intake
Airway support surgery	Very high	May take several weeks to several months	Regular check-ups essential
Obesity management	Moderate	Ongoing management required	Meal portion control required

The treatment method is chosen based on the severity of symptoms; decide after consulting your veterinarian.

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References

[1] Rancan et al. (2013) Canine and Feline Respiratory Medicine, 3rd Edition. Elsevier.

[2] Bannasch et al. (2010) Brachycephalic Obstructive Airway Syndrome: A Congenital and Heritable Disorder in Dogs. Journal of Veterinary Internal Medicine.

[3] Notes on Canine Internal Medicine, 4th Edition. Blackwell Publishing. Chapter 5.10.2 Upper Airway Disorders.