Dr. Utchen, my dog coughs a lot, but seems fine otherwise. The vet says he has chronic bronchitis and that it might be from an allergy. She says he’ll probably always need medication for this. Why can’t this be cured like when people get bronchitis?
Answer: Chronic bronchitis and allergic bronchitis are basically the same thing—chronic means it’s been going on a long time and isn’t really changing very quickly, and allergic means it’s due to some kind of environmental allergy, like pollen, dust mites, molds, etc.
Chronic bronchitis is usually due to some degree of allergy in the first place, although once it’s been going on long enough, there can be some permanent damage to the airways which leads to a reduced ability of the lungs to get rid of mucus and dust, etc., on their own, so a dog has to actively cough it up. And then even if the allergy goes away completely a dog may still have lungs that accumulate too much mucus. It may be worse during different seasons of the year, when allergies or other contaminants in the air (like smoke) are worse, and then better other times of year even though the coughing may never go completely away.
Generally a chest x-ray is taken to arrive at this diagnosis, although the only positive way to know if an allergy is still contributing to the problem is to perform a bronchoscopic exam. This is where a dog is anesthetized lightly and a flexible scope is passed down the trachea into the lungs, by which a sample of mucus from way down in the lungs can be obtained.
Otherwise, dogs with suspected chronic bronchitis are usually treated with antibiotics to take care of any infection that might also be present, and then something for allergies and inflammation in the lungs. Prednisone is a type of cortisone that usually works well to reduce the inflammation of the airways that results from active allergies—and also helps reduce mucus secretion and accumulation in lungs even if allergies are no longer part of the problem—although full doses of this medication can have various side effects. Another medication called Temaril-P, which is a low dose of prednisone plus an antihistamine in the same tablet, can be used without the side effects of taking straight prednisone.
If a trial of antibiotics and allergy medication works well, but the coughing recurs whenever the allergy medication is discontinued, then it is most likely that allergy medication of some kind will be needed continually to minimize allergies and reduce inflammation in the lungs.
Allergy shots can be given to dogs just like people, but while this approach will reduce active allergies in most dogs, it will not reduce residual inflammation that remains in the lungs as a result of prior damage from long-term allergies or irritation from environmental sources like dust and smoke.
We see some dogs whose chronic bronchitis is a result of long term exposure to second hand smoke. I strongly encourage our clients not to smoke around their pets, as not only has chronic bronchitis in dogs been linked to second hand smoke, but lung cancer in cats has also been reported in cats as a result.
As with all chronic conditions that have failed to respond well to treatment so far, a second opinion is always a good idea. There are a number of specialty practices in the Bay area, as well as the Veterinary School at UC Davis, where respiratory specialists can examine your dog.
This is important to consider, because unusual infections, heart disease and other problems involving the larynx (voice box) and trachea — even lung cancer of different forms, some of which are treatable —can all cause coughing in dogs.