Dogs can cough for many reasons — most of them benign. Think of yourself coughing after walking down a dusty path. Your dog will tend to cough then, too! Maybe even more so because he is closer to the dust cloud.
1. Coughing Caused By Allergies
Some senior dogs will develop seasonal allergies that lead them to cough. Our Australian Shepherd, Tia, coughed for about two weeks every fall. I gave her allergy medications, and in about three weeks the cough would go away. Dogs with allergies tend to feel fine otherwise. They don’t have a fever or miss any meals and may cough on and off during the day. Dogs with an allergic cough tend to cough up some mucus or clear fluid, if anything at all.
Some older dogs with allergies will also do what is called a “reverse sneeze.” Instead of expelling air like a regular sneeze, the air goes internally very quickly. At first it may seem like your dog is choking or having an asthma attack. Reverse sneezing is more common in toy and small breed dogs. Brachycephalic dogs with shortened muzzles like Bulldogs are also prone to this. Think of it as a small spasm in your dog’s throat. Any irritant can cause this — cold air when your dog goes outside, dust, excitement or pulling on a collar. You can generally stop the reverse sneeze by gently putting your hand over your dog’s nose. Our Corgi, Flash, would reverse sneeze when she was very excited. There is no health problem from this even if it sounds scary to you.
If, however, your dog coughs frequently during the day or consistently coughs at certain times of day or after certain activities, you need to look into the cause of the cough. Coughing in an old dog can be a sign of an underlying health problem.
Most coughs in old dogs are due to problems in the lungs or the heart. Infectious causes are possible, but often the cough is a result of aging and wear-and-tear on those organs.
2. Canine Influenza Coughs
By the time they have reached senior status, most dogs have built up some immunity to most infectious coughs. Even if they have not had a case of kennel cough syndrome themselves, they have probably been exposed to dogs who have and built up some immunity that way. The primary exceptions are the two types of canine influenza now found in North America.
In 2004, H3N8 canine flu virus was isolated from sick dogs in the United States. With no previous flu virus around, virtually all dogs were susceptible. As is typical of respiratory infections where disease is spread by coughing and sneezing, dogs who were out and about being social were the most likely to be exposed and get ill. Think of a dog training class or a day care situation to be similar to your office. One person coughs, and you all get sick. In the case of your dog, one dog coughs or sneezes and every dog exposed to the droplets expelled can potentially get sick.
There is now a vaccine for H3N8 flu and most dogs have had some exposure, so they have at least a minimal amount of immunity. Then, in spring 2015, a new variant of the canine flu showed up starting in Chicago. This is an H3N2 flu virus from Asia. Suddenly our dogs were potentially being exposed to another new pathogen. Luckily, most dogs handle getting canine flu of either variant well. Even old dogs, as long as they are healthy, seem to handle this illness.
A few senior dogs, especially ones with underlying heart, lung or immune problems, may go on to develop a secondary bacterial pneumonia. Those dogs may need hospital care, with intravenous fluids and antibiotics. Often in these cases, any coughed up discharge will change from clear or white to discolored and thick.
3. Coughing From Heartworms
An infectious cause of a cough that can affect any age dog is heartworm infection. Dogs acquire heartworm through the bite of an infected mosquito. This disease spreads from dog to dog but only with the mosquito intermediary.
Heartworm larvae, called microfilaria, live in your dog’s bloodstream. The adults set up housekeeping in the lungs and heart. Left untreated, heartworm can kill your dog. Dogs with heartworm tend to lose weight and will often cough and have decreased exercise tolerance. Heartworm is diagnosed with a blood test. This is definitely a problem where prevention is key. Treatment involves potentially toxic drugs and a long, quiet recuperation as your dog’s body deals with disposing of the dead (but internal) heartworms. There are excellent preventive medications for heartworm.
Heartworm is a regional and seasonal disease to some extent, because it requires a mosquito carrier. Your veterinarian can guide you to the proper prevention schedule for your dog. Snowbirds need to remember that while mosquito season may end up North, there will still be active mosquitoes down South!
4. Collapsed Trachea Coughing
Some dogs will cough after drinking water. This may be from a collapsed trachea — a condition where the cartilage of the trachea is weak and does not support the rigid structure that is ideal for moving oxygen down to the lungs. A collapsed trachea is more common in toy and small breed dogs and may be present from early on in life or get progressively worse over time. Medical and surgical options for treatment are available. Part of the care for this condition is the use of a harness in place of a collar to prevent further trauma to the trachea.
5. Coughs From Laryngeal Paralysis
Laryngeal paralysis may also cause coughing, panting or choking after a drink. In this case, the nerves and muscles working the larynx to shut it when your dog eats or drinks have basically worn out. With the larynx not always closing to a tight seal, your dog may inhale water or food. This could lead to aspiration pneumonia, though many dogs simply cough. There are surgical treatment options for this and some medical treatments that will help minor cases. Older sporting dogs, especially Labrador Retrievers, are prone to this problem.
There are many theories for why dogs develop laryngeal paralysis. It may be associated with other aging problems of muscles and nerves. It may be related to trauma from collars earlier in life. Any direct trauma to the larynx could cause this.
Dogs with collapsed tracheas or laryngeal paralysis tend to have a difficult time during hot, humid weather. They benefit from having air conditioning. Exercise should be limited in hot weather, as well as excitement.
My son’s elderly Australian Shepherd, Baloo, has some laryngeal paralysis. He still does his mile and a half walk, but we go early in the morning when it is cool. More than a true cough, you notice sort of a wheeze or heavy pant from these dogs. Baloo has had to cut back on some dog sports such as agility (partly due to leg problems; he is 13.5 years old) but he still enjoys barn hunt and short games of fetch on cool days.
6. Coughs From Pneumonia
Bacterial and fungal infections can hit dogs of any age — leading to pneumonia. Dogs with pneumonia of any underlying cause will act ill. They will have a fever, generally a “wracking” cough and may not want to move around or eat. Your veterinarian may need to take radiographs (X-rays) to diagnose the pneumonia and do some bloodwork or tracheal washes and cultures. Dogs with pneumonia tend to have a “wet” cough and may cough up discharges that are thick and discolored.
Diagnostics are important to find the “villain” behind the pneumonia, so treatment can be accurate and specific. Medical therapy, such as antibiotics, along with oxygen and fluids for severe cases is important.
7. Cancer Coughs
Cancer can cause a cough in an older dog. Primary lung cancer is quite rare in dogs. It is primarily seen in dogs exposed to environmental contaminants, such as secondhand cigarette smoke. If you smoke, consider quitting for your dog’s sake if not your own.
The lungs are a frequent site for cancer to spread or metastasize to, though. For example, a dog with bone or breast cancer may have cancer spreading to the lungs. Radiographs are the common way to diagnose cancer problems. Treatment will vary with the type of cancer.
8. Coughing Because Of Heart Problems
One of the most common causes of coughing in old dogs is a heart problem. The exact type of heart problem will vary with the individual dog. Toy breeds and small dogs are prone to congestive heart failure and valve disease. Toy Poodles and Cavalier King Charles Spaniels tend to have heart problems in their old age.
Large and giant breed dogs are also prone to some heart problems — including cardiomyopathy, a disease of the heart muscle. Doberman Pinschers, Boxers and Old English Sheepdogs are breeds that come to my mind right away for senior heart problems.
There are often common features for a heart-related cough. If there is any discharge, it tends to be white or clear. You might notice that your dog coughs more at night when he lies down. Actually you may notice coughing any time he lies down — day or night. Some dogs show a blueish tinge to their gums instead of the normal pink. You might realize your dog is much less active than previously. Some of that slowing down may be due to other factors, such as arthritis, but it is important to rule out a cardiac cause. Dogs with severe heart disease often lose their appetite and will lose weight.
Diagnosis starts with a thorough auscultation (listening to internal body sounds). Your veterinarian will evaluate your dog’s heart and lung sounds with a stethoscope. Next, radiographs may be taken. Generally multiple views will be evaluated to rule out lung disease and cancer. An EKC, or electrocardiogram, will check out how your dog’s heart is beating. Another possibility isan ultrasound to evaluate the heart muscle and action.
Believe it or not, dogs can be fitted with pacemakers if their heart problem is due to an irregular beat. However, for most heart problems in senior dogs, medical therapy is the ideal treatment. Just like people with heart problems, your dog may be put on a diuretic and a special diet and then medications to help the heart function more efficiently. Most of the heart medications used in people were originally studied in dogs, so turnabout is fair play!
As you can see, a cough in a senior dog can have many causes. Most of these coughs are treatable once you have determined the exact cause. You should not give any cough medications (including human over-the-counter ones) until you have consulted your veterinarian. There are cases where a cough is helpful and suppressing it may harm your dog.
Switching to a harness from a collar helps most dogs. Plan your exercise — in type, amount and time. Your senior canine may be happier with a 1-mile stroll in place of a half-mile run. He may need to back off on some of his performance sports — maybe doing one agility run a day versus two. On hot, humid days, your coughing senior dog is best off where it is cool and dry. A room with an air conditioner is perfect. If respiratory illnesses are “going around,” consider leaving your pet home and not going to training class, an event or doggy daycare.
Luckily, most senior dog coughs are treatable, and while your dog may never be “cured,” you can control symptoms and make him comfortable.
Posted by: Dr. Deb M. Eldredge
Featured by: RayTango/iStock/Thinkstock