SYMPTOM
Stridor
Owners may observe stridor in their pet.
Various conditions
This symptom can occur in multiple conditions and warrants further assessment.
Laryngeal Paralysis
Failure of the vocal folds to move apart normally during inspiration, most often from age-related nerve degeneration in older large-breed dogs, particularly Labrador Retrievers and other retriever types, narrows the airway and produces a harsh, high-pitched inspiratory sound. It frequently follows a period of voice change or exercise-related noisy breathing before becoming more pronounced.
Brachycephalic Airway Conformation
Flat-faced breeds such as French Bulldogs, Bulldogs, and Pugs are born with narrowed nostrils and an elongated soft palate, and the resulting extra breathing effort commonly causes the laryngeal saccules to turn outward (evert) over time, narrowing the airway further at the level of the larynx. This produces a stridor that is often noticeable from a young age and worsens with heat, excitement, or exercise, reflecting both inherited conformation and the secondary airway changes it drives.
Tracheal Collapse
Weakening and flattening of the cartilage rings supporting the trachea, common in small and toy breeds such as Yorkshire Terriers and Pomeranians, narrows the airway and produces harsh, often honking, respiratory noise. Signs typically progress gradually over months to years and can be worsened by excitement, warm weather, or collar pressure.
Laryngeal or Nasopharyngeal Mass
Growths within the larynx or upper throat, including local extension from thyroid carcinoma, gradually narrow the airway and produce a progressively worsening high-pitched breathing sound. This pattern is more common in older dogs and tends to be accompanied by a gradually changing bark.
Why timing matters
Early observation
Early recognition allows prompt assessment and intervention if needed.
Later presentation
Persistent or worsening signs may indicate progression requiring attention.
The significance of this symptom depends on its context, duration, and associated findings.
Conditions commonly associated
Laryngeal Paralysis
The harsh, high-pitched breathing noise results from air turbulence through the narrowed laryngeal opening.
Laryngeal Paralysis in Dogs
Stridor in laryngeal paralysis arises when the cartilages of the larynx fail to open fully during inhalation, creating turbulent airflow through a narrowed airway. This high-pitched inspiratory sound tends to become more pronounced during exercise or in warm conditions when breathing effort increases.
Feline Asthma
Stridor can occur during acute episodes of feline asthma when severe airway constriction and inflammation create turbulent flow in the upper airways. This sound may accompany wheezing and increased respiratory effort during periods of bronchospasm.
Pneumonia
Pneumonia can produce stridor when inflammation and fluid accumulation affect the upper airways or when the increased work of breathing creates turbulent flow through the larynx and trachea. This presentation tends to occur alongside other respiratory signs such as coughing and increased respiratory rate.
Megaoesophagus
Stridor may be observed in megaoesophagus when accumulated food material in the dilated oesophagus compresses the adjacent trachea, or when aspiration of oesophageal contents causes upper airway inflammation and partial obstruction. This relationship reflects the close anatomical proximity of the oesophagus and respiratory structures.
Acromegaly in Cats
Growth hormone excess can thicken the soft tissues of the throat, producing a harsh, noisy sound on breathing.
Thyroid Carcinoma in Dogs
A tumour narrowing the airway at the level of the voice box produces a harsh, high-pitched noise on breathing in.
When to explore further
When the symptom is persistent or worsening
When other signs are present alongside
When daily activities or quality of life are affected
When there is uncertainty about the cause
Noting when this symptom occurs, any triggers, and how it changes over time can provide useful information for veterinary discussions.
Last reviewed: 24 April 2026 · Dr Alastair Greenway MRCVS