Bronchitis in dogs is a common illness that affects the upper airways and causes coughing. If the cough lasts more than two months, it's generally referred to as chronic bronchitis.
To understand the disease, it's first important to know about the basic anatomy that's involved. Air enters the body through the mouth or nose and flows through the trachea, also known as the windpipe. The air then travels into smaller air passages called bronchi before reaching the smaller bronchioles and, finally, the tiny alveoli, where oxygen enters the bloodstream.
Bronchitis is a disease characterized by inflammation in the bronchi and bronchioles — the parts of the lungs through which oxygen-rich air travels. Inflammation in these airways leads to mucus production, coughing and irritation. This stimulates the production of more mucus and leads to a cycle of constant inflammation.
Infectious tracheobronchitis is a related disorder that involves the trachea, bronchi and bronchioles. It's more commonly associated with acute disorders similar to kennel cough. Chronic bronchitis, by contrast, typically doesn't involve the trachea. It's important to recognize this difference as the disorders may look similar but have different causes and treatments. Your veterinarian will be the best resource for distinguishing between and diagnosing both.
Dogs with bronchitis may have a cough that's wet, dry or honking. In some cases, pet parents might confuse the cough for gagging or vomiting, so it's helpful to take a short video of the behavior for your veterinarian's benefit.
While your dog's coughing can seem minor, it might indicate a problem. At the first sign of a persistent cough, bring your dog to the vet. This is particularly important if the cough's characteristics change — if it gets more frequent, louder or softer, wetter or dryer.

Bronchitis in dogs can be caused by anything that irritates the airways or otherwise stimulates an inflammatory reaction. The key is to distinguish it from other causes of coughing, such as:
In many cases, these disorders can exacerbate chronic bronchitis. The true cause of the disorder, however, is the inflammatory cycle that's initiated and perpetuated by the reactivity of the dog's respiratory passages.
Note that asthma is quite distinct from chronic bronchitis and isn't common in dogs. Your veterinarian can help explain each of these problems as it pertains to your dog's specific case.
Vets diagnose chronic bronchitis based on a variety of factors, including the dog's health history and a physical exam. To help make a diagnosis and rule out other causes of coughing, they use the following tools: