What Causes Older Dogs to Cough?

The occasional cough can be your dog's natural way to clear his airways, but repeated bouts of coughing in older dogs require attention as it could signal something serious. While the causes of canine coughing in aging dogs can be various, they can be narrowed based on the dog's breed, type of cough, how long it lasts and the circumstances in which it occurs. If your older dog has a cough that doesn't go away, your best bet is to play it safe and take your dog to the veterinarian.

As dogs age, their immune system may weaken and their lungs lose elasticity, making them more prone to respiratory diseases. A persistent, hacking cough in an older dog may be indicative of bronchitis, the inflammation of the lining of the dog's large airways. The inflammation can be caused by viruses, bacteria or exposure to irritants such as allergens, secondhand smoke or foreign bodies. Coughing is often noticed when the dog is exercised or excited or during the night and upon waking. It also commonly occurs with excitement or exercise. Untreated, bronchitis in older dogs can rapidly turn into pneumonia.

Pesky parasites usually are seen in debilitated animals or those with a weakened immune system. Elderly dogs are particularly prone to whipworms, tapeworms and heartworms. Among these parasites, heartworms are quite concerning as they invade the dog's blood vessels and heart and potentially can make a dog very sick. Coughing along with fatigue and an overall poor physical condition, are common symptoms indicative of a heartworm infestation. A trip to the vet is required if these symptoms are present.

Also known as windpipe, a dog's trachea is a flexible tube made of several rings of cartilage displayed in a similar fashion as seen in a vacuum cleaner's hose. Over time, the trachea may weaken and flatten resulting in collapse, which leads to gagging and a honking type of cough especially seen when the dog is excited or pulling on the leash. According to the American College of Veterinary Surgeons, particularly predisposed to this condition are middle-aged or older dogs of the following breeds: Yorkshire terriers, Pomeranians, poodles and Chihuahuas.

As dogs age, their risk for heart disease dramatically increases. It's estimated that the incidence for chronic valve disease increases to more than 60 percent, in aged dogs and the most common symptoms observed is coughing, explains John E. Rush, a board certified veterinary cardiologist working for Tufts University School of Veterinary Medicine in Grafton, Massachusetts. Coughing in dogs with heart problems may be more prominent at night when the dog is lying down, but also can be seen after exercise or excitement.

As dogs age, they are more predisposed to tumors. Older dogs, more than 10 years of age, are predisposed to adenocarcinoma of the lungs, better known as lung cancer. While lung cancer can affect any breed of dog, boxers are particularly at risk for this condition. Affected dogs may have difficulty breathing, a poor appetite, weight loss and they may appear lethargic and cough up blood. Most often, lung cancers in dogs are spread from other organs affected by cancer through the bloodstream, a process known as metastasis.