By Sarah Wooten, DVM
Wheezing is caused when something blocks the normal flow of air in and out of the airway, resulting in a whistling sound as a dog breathes. The blockage can be in either the trachea (windpipe) or large bronchi.
Constricted airways from asthma, allergies, mucus, foreign bodies, or infection can all result in wheezing. If a dog feels like he can’t get enough air, he may panic, or he may find a spot to lie down to try to breathe better.
Non-emergency wheezing usually lasts only a few seconds. It may resolve on its own, or return intermittently, necessitating a trip to the veterinarian to sort things out.
If your dog is wheezing continuously, or his gums have a blue-ish tint indicating that he isn’t getting enough oxygen, or if your dog seems uncomfortable breathing, those are signs that the wheezing is potentially life-threatening; you will need to take your dog to an emergency veterinarian immediately.
The Most Common Causes of Wheezing in Dogs
Many things can cause wheezing in dogs. The following is a list of the most common causes.
Wheezing Related to Infectious Disease
Dogs can contract parasites that live in the lungs and airways, causing secondary conditions due to irritation of the respiratory tissues. Heartworms can cause wheezing, as can aberrant migrations of hookworms or roundworms.
One common cause of wheezing and reverse sneezing is nasal mites, a common parasite that is highly infectious between dogs. Dogs can carry nasal mites for years and the only sign you may see is wheezing or sneezing when the dog gets excited.
Bacterial and viral diseases can also cause wheezing and coughing. Dogs with wheezing due to infectious disease typically have a history of being around other dogs, such as being in an area where other dogs frequent, like the dog park, doggie daycare, or groomer.
Wheezing Related to Allergies
Dogs can have allergies just like people. Pollen, mold, dust mites, cigarette smoke, etc. can all cause allergies in dogs, including allergic asthma, which causes dogs to wheeze from constricted airways.
Dogs that wheeze due to seasonal allergies may only have problems during part of the year.
Wheezing Related to Collapsing Trachea or Bronchitis
In the dog, the windpipe is comprised of cartilage in a C-shape that is closed by a membrane that is flexible. In some small breed dogs, that membrane can get loose or floppy over time, and as the dog breathes in, the trachea can collapse on itself, narrowing the airway and making it more difficult for the dog to breathe. Collapsing trachea is common in Pugs, Maltese, Shih Tzus, Lhasa Apsos, and other small, short-nosed breeds. Excitement or exercise can make this type of wheezing worse.
Chronic bronchitis can also cause scarring in the airways, which can make the bronchi less flexible, leading to constant wheezing and coughing.
Wheezing Related to Heart Disease
Dogs that have congestive heart failure due to heart valve disease can also wheeze due to fluid build-up in the lungs. Dogs that have wheezing due to heart failure are typically older, though they can also be young, in rare instances. They tend to have a low energy level along with a persistent cough.
Wheezing Related to a Foreign Body
Wheezing due a foreign body in the airways is always an emergency. This tends to be a problem in dogs that chew on bones, balls, or toys; especially younger dogs. Dogs that like to run with balls in their mouth have been known to accidentally suck the ball down their throat.
If a foreign body completely obstructs the airway, a dog will pass out from the lack of oxygen. If the object only partially obstructs the airway, the dog will wheeze violently and may panic.
If you suspect that your dog is wheezing due to something he inhaled, take your dog to a veterinarian immediately for treatment. This issue cannot be resolved at home.
Diagnosis of Wheezing in Dogs
A veterinarian will need a detailed history from you – events leading up to the wheezing, when your dog first started to experience breathing problems, etc. Be sure to know your dog’s travel history, any medications that your dog is on, including heartworm prevention, and your dog’s vaccine history.
The physical exam, and possibly laboratory testing, will be used to determine the cause of your dog’s wheezing. Laboratory testing may include bloodwork, x-ray, and/or other testing as needed.
Treatment for Wheezing in Dogs
Treatment depends on the cause of the wheezing. With foreign bodies, your veterinarian will likely sedate your dog and remove the foreign body with medical instruments. If your dog is wheezing due to infectious causes, treatment will be aimed at eliminating those infections.
If the wheezing is due to allergic asthma or bronchitis, your veterinarian will talk to you about medications that can be used to control that condition, and things you can do at home to reduce allergens for your dog, such as vacuuming, HEPA air filters, etc.
If the wheezing is due to heart disease, your veterinarian may prescribe medications to help the heart pump stronger and more easily. Wheezing due to a collapsing trachea is treated with cough medication and by controlling the pet’s environment; i.e., making sure the pet has a cool place to rest where it cannot get overheated.
An Ounce of Prevention…
Some causes of wheezing cannot be prevented. However, infectious causes, such as kennel cough, heartworm disease, hookworms, roundworms, and highly infectious viruses such as distemper, can be prevented with proper vaccination and internal parasite control.
Heartworm infection can be fatal – signs like wheezing may not be present until the infection has gone too far for treatment options. When your veterinarian reminds you to get heartworm prevention for your dog, make sure to get it and give it to your dog regularly, as advised by your veterinarian, and follow all vaccine recommendations for your dog.