Chronic Cough in Dogs and Cats: How to Classify and Localize It

A dog has been coughing for several weeks. The owner describes it as “honking,” but the patient is otherwise comfortable. Another patient has a soft cough with abnormal lung sounds. 

Are these simply different descriptions of the same clinical problem? 

Not necessarily. 

For a coughing dog or cat, how the cough sounds, when it occurs, how long it has been present, and what accompanies it can help narrow the differential diagnosis. A structured approach to classification and localization can make the subsequent diagnostic work-up more targeted. 

Start With Duration and Character 

In veterinary patients, cough is generally considered acute when present for less than 2 months and chronic when it persists for at least 2 months^[1]. Duration alone does not identify the cause, but it helps frame the clinical approach. 

The character of the cough can provide additional clues. A cough may be described as dry, moist, honking, or productive. A moist cough producing sputum suggests excess fluid within the airways and can point toward conditions such as pneumonia or pulmonary edema. However, owners may not recognize a productive cough because dogs and cats commonly swallow expectorated material^[1]. 

A loud cough generally points toward large airway disease, whereas a softer cough is often associated with lower airway disease^[2]. 

Ask What Triggers the Cough 

History-taking should go beyond asking, “How long has your pet been coughing?” 

Ask whether coughing occurs during: 

• Excitement or exercise 
• Eating or drinking 
• Rest or sleep 
• Episodes of respiratory difficulty 

Also ask about the sound of the cough and whether the animal has wheezing, stridor, stertor, nasal discharge, or sneezing^[1],[2]. 

In cats especially, careful questioning may be necessary to distinguish coughing from vomiting or retching^[1]. 

The trigger can be clinically useful. A cough associated with eating or drinking, for example, provides a different diagnostic direction from one repeatedly triggered by excitement. 

Respiratory or Cardiac? 

Once the cough has been characterized, consider whether the primary problem is respiratory or cardiac. 

Respiratory causes may originate from the upper airway, lower airway, pulmonary parenchyma, or pleural space. Upper airway conditions associated with coughing include rhinitis, laryngeal disease, tracheal collapse, and infectious tracheobronchitis. Lower airway causes include chronic bronchitis, bronchomalacia, pneumonia, idiopathic pulmonary fibrosis, eosinophilic bronchopneumopathy, and lungworm disease^[2]. 

Cardiac disease also needs consideration, particularly in dogs. Left atrial enlargement can compress the mainstem bronchi, while congestive heart failure can contribute to coughing through pulmonary edema and stimulation of pulmonary receptors. In contrast, coughing is not a common clinical sign of cardiac disease in cats^[1]. 

Let the Physical Examination Localize the Problem 

Physical examination can provide important localization clues before advanced diagnostics are considered. 

Look for nasal discharge, sneezing, abnormal nostril airflow, and facial asymmetry. Inspiratory stridor may suggest laryngeal disease, whereas nasal discharge, abnormal nostril airflow, and sneezing can point toward nasopharyngeal disease^[1],[3]. 

Auscultate both the heart and lungs. Murmurs, arrhythmias, abnormal pulmonary sounds, jugular pulses, hepatomegaly, or ascites may increase concern for cardiac disease. However, pulmonary crackles are not specific to cardiac disease and may also occur with pulmonary fibrosis, inflammatory pulmonary disease, or non-cardiogenic pulmonary edema^[1]. 

Tracheal palpation can sometimes induce coughing in patients with tracheal disease, but this finding is not definitive. Dogs with other respiratory diseases, and even normal dogs, may cough when the trachea is palpated^[1]. 

The Clinical Bottom Line 

Cough localization starts before imaging or invasive testing. Duration, sound, triggers, associated respiratory signs, and cardiovascular findings should be considered together rather than in isolation. 

The goal is not simply to label a cough as “dry” or “productive.” The goal is to determine where the problem is likely originating and whether respiratory or cardiac disease is contributing, so the next diagnostic step can be selected appropriately.

References:

1. Hsieh BM, Beets AK. Coughing in small animal patients. Frontiers in Veterinary Science. 2020 Jan 21;6:513. https://www.frontiersin.org/journals/veterinary-science/articles/10.3389/fvets.2019.00513/pdf
2. Martin M, Pereira YM. Approach to the coughing dog. In Practice. 2013 Oct;35(9):503-17. https://www.researchgate.net/profile/Mike-Martin-7/publication/275001097
3. Hunt GB, Perkins MC, Foster SF, Barrs VR, Swinney GR, Malik R. Nasopharyngeal disorders of dogs and cats: a review and retrospective study. Compendium. 2002 Mar;24(3):184-203. https://www.researchgate.net/profile/Richard-Malik/publication/282493677