Why Is My Dog Coughing Up Foam?
Your dog starts coughing, and then, finally, he coughs up a white, foamy liquid. What is happening?
Why Dogs Cough
Like humans, dogs cough to clear their throats. They cough to clear the respiratory tract and get rid of irritants, secretions, foreign particles, viruses, fungi, and bacteria.
The mechanism of coughing in humans and dogs is also the same: there's a fast inhalation, followed by an exhalation, accompanied by a strong release of air.
In humans, coughing may be voluntary or involuntary. But in dogs, there is no such thing as a social cough; they don't "clear their throat" to get somebody's attention or start a conversation. A cough in dogs is something that needs attention, especially if it happens again and again throughout the day, or with other accompanying symptoms.
There may be several possible causes for coughing. In the case of occasional coughing, the dog may be simply choking on some food, or his respiratory tract may be just reacting to some temporary irritant. This kind of cough is often short-lived and stops once the airway is clear. However, the dog may have a hard time clearing its throat if a foreign item such as a foxtail is present; if so, the dog will need veterinary intervention.
A cough is called "productive" when it's capable of bringing up secretions. A non-productive cough is dry, with no secretions produced.
Often, owners confuse a productive cough that brings up foam with vomiting. They will, therefore, tell their vets that their dog is vomiting white foam, without mentioning the important detail that the dog was coughing before the foam made its way up.
Viruses and bacteria provoke coughing as part of their survival strategy; coughing helps microbes spread to other dogs. So a coughing dog should be isolated from other dogs to prevent possible contagion, just to be safe, before he has a confirmed diagnosis.
Conditions That May Cause Dogs to Cough Up Foam
Any dog coughing up foam should see the vet, because some serious conditions can cause this behavior. Some causes are described below, with videos to illustrate. These videos may disturb sensitive viewers. Discretion is advised.
If your dog has been to the vet, groomer, dog park, or kennel recently, he might have contracted kennel cough, also known as bordetella because it can be caused by Bordetella bacteria. The incubation period for this upper respiratory infection is generally three to ten days. This condition is easily transmitted from one dog to another. Typically, the dog will cough repeatedly, and end up gagging and then retching, bringing up white, foamy saliva. This foam may be left as a puddle on the floor, or the dog may swallow it.
There is a bordetella vaccine for dogs, but it is not terribly effective, because it covers only a few organisms out of the many bacteria and viruses that cause kennel cough.
When a dog has advanced heart disease or heart failure, his circulation is affected. Heart disease in dogs often causes a cough, and then as it progresses, other complications such as ascites (buildup of fluid in the belly). This cough may be triggered by the enlarged heart pushing against the trachea. It may begin as a non-productive cough, but may then turn productive as heart failure sets in, and often occurs at night.. Lack of proper circulation will soon cause blood to pool in the lungs, explains veterinarian Carol Osborne. This causes the dog to cough up blood mixed with mucus and saliva, which appears as a pink, foamy mixture. If your dog has an unexplained recurrent cough, have him seen by a vet, even if there are no signs of pink foam or other symptoms. You don't want your dog's condition to deteriorate, reaching the point of the dog in the video. Heartworm disease may also cause a "heart cough."
Bloat (stretching and twisting of the stomach) is a life-threatening condition, and dog owners should all learn about its symptoms. It's more common in deep-chested breeds. While bloat typically causes a distended abdomen, pacing, and unproductive retching, some sick dogs may be able to retch and bring up foam. In the video below, you'll see a dog suffering from bloat, and there is a moment where the camera shows some liquid foam the dog brought up. Fortunately, the dog in the video survived, but mortality rates are pretty high, especially when treatment is not sought in time.
Bilious Vomiting Syndrome (Vomiting Yellow Foam)
As mentioned previously, many owners confuse coughing with vomiting. Vomiting may also be confused with coughing. When a dog has bilious vomiting, he may wake up in the middle of the night to vomit and retch, leaving a small puddle of whitish or yellowish foam. Such vomiting can also happen during the day, especially in dogs who are fed only once a day. This yellow-foam vomiting is caused by the buildup of bile resulting from the stomach being empty for too long. According to Vet Info, some dogs can be helped by simply giving them a bedtime snack. Dogs with this problem who are fed once a day may benefit from twice-a-day feedings.
In the video, notice the stomach contractions as the dog gets ready to vomit.
What if a dog drinks a lot of water and then vomits foamy liquid back up? According to veterinarian Dr. Kara, this may happen to dogs who vomit often and are exposed to stomach acids. Their esophageal sphincter may swell and become less effective in dealing with an overfull stomach (as when the dog drinks too much). Placing large rocks in the water bowl, to prevent the dog from gulping down loads of water at once, may help. An acid reducer may also help. However, in some cases, the reflux may be due to megaesophagus, Consult with your vet.
While kennel cough is caused by viruses or bacteria, coughing can also be caused by a fungus. Valley fever is a fungal condition quite common in the desert Southwest, caused by spores found in the soil, that causes a stubborn cough. The disease may cause fever and disseminate to the joints. The cough may be somewhat similar to kennel cough, with coughing followed by the release of mucus. While in kennel cough the body is trying to expel bacteria or viruses, in valley fever it is trying to get rid of the fungus. At least valley fever is not contagious from one dog to another.
As you can see, there can be several causes for coughing and bringing up foam. Because many conditions can be serious, it's always recommended to have the dog see a vet.
Disclaimer: the above article is not to be used for the purpose of diagnosing your dog. It's only the result of my research on the topic using books and online resources. If your dog is coughing, please see your vet immediately for proper diagnosis and treatment.
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