Experienced and professional animal trainer provide their insights in answering this question :
A. It could be kennel cough, worms or a heart or respiratory problem. I would recommend having a check up with your vet when they are open.

How to Identify Common Pet Problems ?

Our sources include academic articles, blog posts, and personal essays from experienced pet care professionals :

“In some cases, dogs with respiratory illness such as kennel cough (a canine infectious respiratory disease complex) or brachycephalic airway syndrome can cause dogs to vomit a white foamy substance,” she adds. Contact your veterinarian if your pup is vomiting (or coughing up) white foam, Dr. McCullough recommends.
If your dog is foaming at the mouth, it is recommended that you make an appointment with your veterinarian as soon as possible. Causes of foaming of the mouth in dogs can be due to mild issues or more severe issues, such as dental disease, a seizure or rabies infection.
The classic symptom of kennel cough is a dry hacking cough, often described as a “goose-honk” cough. Many dogs will cough in small fits until they bring up white frothy phlegm. Depending on the dog and severity of infection, some animals remain normal in demeanour apart from the cough.
Dogs with Kennel cough tend to have a deep, dry, hacking cough along with possible sneezing, snorting, gagging and in some cases, vomiting. Contact with other dogs is the primary way to get the highly contagious viral or bacterial infection that causes Kennel cough.
The most common sign of tracheal collapse is a persistent, harsh and dry cough, sometimes described as a “goose-honking” cough. The signs may progress to a wheezing noise when breathing in, or in severe cases, difficulty breathing, gums or tongue turning blue, or fainting.
Dog Foaming

It`s white and hanging off either side of your dog`s mouth. In actuality, dog foaming is a product of dog drooling. Foam or froth is simply drool that has been infused with air. This can happen due to dog panting or other kinds of heavy breathing.

The good news is that the average patient with acquired laryngeal paralysis is at least 10 years old and the progression of the neurologic weakness is fairly slow. This means many patients will live their normal lifespan before further neurologic weakness becomes a problem.
The most obvious symptom of kennel cough is a forceful, hacking cough, which will often sound like your dog has something stuck in their throat. The cough can be dry and hoarse or productive, in which case it can be followed by a gag, swallowing motion or the production of mucus.
Kennel cough usually causes a dry, hacking cough, while pneumonia typically causes a cough with phlegm. Kennel cough may also cause sneezing, runny nose, and watery eyes, while pneumonia may cause chest pain and shortness of breath.
Your pup could have a virus, bacterial infection, or another underlying health condition. While most health issues can be treated or managed, a recurring cough should not be ignored. Set up an appointment so your veterinarian can examine and diagnose your dog.
The occasional cough in an otherwise healthy dog is usually nothing to worry about. But just like us, when a dog`s coughing becomes a constant or recurrent problem, it can be a sign of serious illness.
Encourage Your Dog to Rest

Adequate rest is one of the best remedies for kennel cough. If your dog gets plenty of sleep, it will give his body a chance to fight the virus and recover properly. Put your dog in a room by himself, away from kids and other pets. This way, he will not be disturbed while trying to rest.

But in truth, many dogs live a good life with a collapsed trachea (windpipe) for years. Only at its most severe stage is the condition life-threatening. Although there`s no cure, a collapsed trachea can be managed with medication, lifestyle adjustments, and sometimes surgery.
Kennel cough is a brief, generally opportunistic, and self-limiting syndrome that rarely leads to significant complications for dogs. Collapsing trachea, on the other hand, is potentially more serious — and it is very common.
Gastritis is defined as inflammation of the lining of the stomach. It may occur as a short episode (acute) or have a long duration (chronic) and may be associated with underlying conditions that are more serious.
Foaming or frothing at the mouth occurs when excess saliva pools in the mouth or lungs and is mixed with air, creating foam. Unintentional foaming at the mouth is an extremely uncommon symptom and a sign of a serious underlying medical condition that requires emergency medical care.
As dogs age, the cartilage rings that make up the trachea become flattened. This narrows the space inside of the trachea and makes it more difficult for air to pass through. As a result, collapsed trachea in dogs may cause a goose honking cough, gagging, and sometimes even respiratory distress.
The most distinctive symptom of kennel cough is a loud, hacking cough or retch. Other common symptoms are runny nose, eye discharge, and sneezing. In more severe cases, or if left untreated, kennel cough can cause decreased appetite, lethargy, depression, and fever.
GOLPP is a progressive degeneration of nerves. Over time, hind-end weakness and generalized muscle wasting will occur. This will slowly progress over several years. This type of neurologic degeneration is not painful, and affected dogs are still bright, alert, and happy.
The common clinical signs of laryngeal paralysis may include: Noisy or raspy breathing. Excess panting. Coughing.
How would I know if my dog has laryngeal paralysis? Laryngeal disease may cause the following clinical signs: exercise intolerance, noisy breathing, coughing and gagging, change or loss of voice.
Congestive heart failure is when a dog has edema of the lungs due to heart disease. Among other symptoms, this results in a wet, phlegmy cough caused by the excess fluid.
Some dogs will be able to fight off the disease without medical intervention. However, if left untreated, the disease has the potential to develop into something worse, such as pneumonia. It is always the safest bet to have the dog treated by a vet as soon as possible.

Relevant Questions and Answers :

the most relevant questions and answers related to your specific issue

Q. My new puppy is coughing a lot and I think it is Kennel Cough. Could it be?
ANSWER : A. Kennel Cough is similar to the human cold, and it can be caused by three categories of microorganisms.

1. Bordetella Bronchiseptica: A small bacteria which can result in bronchitis and severe cough in dogs.
2. Canine Adenovirus: A serious and contagious virus.
3. Canine Influenza Virus: An extremely contagious virus causing mild to severe respiratory symptoms in dogs.
Kennel Cough has its own course of 1 to 3 weeks and can be managed medically.

Close environments with several dogs can increase the chance of dogs catching the cough. Kennel Cough vaccination is aimed mostly at preventing the Bordetella infection through an inhalant or injection vaccination. Although not 100% effective, it should be recommended in all dogs that spend time around other dogs, even the park is considered one of these social occasions.

Kennels have their own policy with regards to Kennel Cough vaccinations and should always be contacted well ahead to understand and comply with their requirements before the stay of your dog.
If you suspect that your dog has caught Kennel Cough, you should see your veterinarian. Your dog might benefit from certain medications to speed up his recovery. These might include antibiotics, anti-inflammatory drugs, and cough suppressants at your vet’s discretion.

Q. My C. K. Charles has an asmathic cough. Ok most of the day, but worse in hotter rooms in the evening. What’s wrong?
ANSWER : A. Coughing in dogs can be caused by a number of things including allergies, asthma, illness such as Bordetella (kennel cough) or even lung and heart problems.

Allergies and asthma can cause a dog to have a raspy cough, and they may wheeze, sneeze or have running noses or trouble breathing when active or in an area where the allergen is present. Your vet can determine if an allergy or asthma is present and provide medication as needed to help with symptoms.

Bordetella can also cause a deep hacking cough, and is common in dogs that frequent doggy day cares, kennels or dog parks. The causes can be bacterial or viral, and treatment depends on if any secondary symptoms such as fever or dehydration is present. Treatment involves cough suppressants from your vet, or even antibiotics and fluids to treat secondary illnesses. Other illnesses such as heartworm may cause a chronic cough and exercise intolerance and should be looked for if your dog is not already on a heartworm preventive.

Small dogs are also prone to a condition called collapsing tracheas, and Cavaliers are very prone as a breed to heart and lung issues. Collapsing tracheae often cause a gasping or hacking cough when excited or active, and may require treatment if they become problematic. Heart and lung problems such as heart failure or genetic abnormalities can also cause coughing as a sign of the illness. Your vet can perform a complete exam to check the health of the lungs and heart.

Q. My dog keep hacking like a cough or something in her throat, what can I do?
ANSWER : A. Hacking and coughing can be caused by a number of things ranging from foreign bodies such as twigs stuck in the mouth or throat, to infections or illnesses such as Bordetella or Kennel cough, common in dogs that frequent kennels, dog daycare or dog parks. In older dogs, heart and lung issues can also be indicated by a cough that does not go away.

If you think there may be a foreign object stuck in your dog’s throat, you can sweep a finger gently through the back of the mouth or throat if your dog will let you. If something feels stuck and is not easily moved by the finger, it is best to contact your vet to have the object safely removed. This usually requires sedation so that your dog does not become panicked or move, causing the object to become further stuck or cut the throat.

If your dog is showing other symptoms of illness in addition to the cough such as runny nose or eyes, fever, lethargy or changes in appetite, it may indicate a viral or bacterial illness such as kennel cough. These are usually treated with a cough medication in severe cases, plus rest and treatment of any additional symptoms until the condition improves. In bacterial causes, antibiotics may also be given to help your dog feel better.

If your dog has a constant cough that does not go away, or has had changes in ability to exercise, breathing, or appears to have swelling around the chest or abdomen, in may indicate a lung or heart issue. Your vet can thoroughly examine your dog for any signs of heart or lung problems and can then offer care as needed depending on the cause.

Q. My Japanese Chin is coughing its a dry cough
ANSWER : A. A dry hacking cough may indicate an issue with the lungs or throat, and may be due to irritation (such as allergies), illness such as kennel cough, or even functional problems with the respiratory system. It is best to schedule an appointment with your vet who can look into your dog’s throat and may also recommend bloodwork or an X-ray to check for common problems if the coughing does not resolve on its own in a few days or if it worsens. Until you can get to the vet it may be best to restrict activities that lead to coughing (such as too much exercise) as well as to keep her hydrated and eating.

Q. My dogs have a hacking cough. What can I give them to treat?
ANSWER : A. It depends on what is causing the cough. If it is due to kennel cough then this is caused by a virus so there is no treatment it is just time, some vets will prescribe antibiotics or antiinflammatories for secondary problems caused by the virus if required.
If it is a dry hacking cough it could also be related to heart problems which can have serious effects. It is best that it is examined by your vet to rule out a heart condition.

Q. Why does my dog cough only at night it’s a hacking cough like he is gagging
Thanks
ANSWER : A. Depending on his age and how long this condition has been going on it could be Kennel cough, heart failure, lung tumor or heartworm. all the condition other than Kennel cough are very serious and require veterinary attention. kennel cough usually goes away without treatment within 2 weeks.

Q. Dry hacking cough with foamy white spit-up on occasion
ANSWER : A. It could be kennel cough, worms or a heart or respiratory problem. I would recommend having a check up with your vet when they are open.

Q. My dog has been coughing for 3 days. She has never been to a kennel so I know that it is not kennel cough. Why is she coughing so much?
ANSWER : A. It is difficult to be able to help you without some important information such as the age of your dog, the onset, if there are any other medical conditions, if the cough is dry or moist, if there are any other resp noises and if your dog is eating normally. I would suggest that you have him checked over, as coughing can be secondary to heart conditions , especially in elderly patients and it can be life threatening too.