The collapsed or collapsing trachea is most commonly seen in toy breeds and very small breeds of dogs such as the miniature Poodle, Yorkshire Terrier and the Pomeranian. It is also very common in the short muzzled or brachycephalic dogs such as the Shih Tzu, Pug, Bulldog, Boston Terrier and the Pekingese.
Collapsed tracheas can also be seen in almost any other dog that has an injury to the throat area, has a severe or persistent problem with kennel cough or another upper respiratory infection or disease, is extremely obese or has an enlargement of the heart that pushes against the trachea. In rare cases dogs that have under gone a surgical procedure and have had a breathing tube placed down the throat may have problems with collapse trachea later if the tube was incorrectly inserted or if the dog already had the condition and the insertion of the tube made it more severe. [...]