9 Signs Your Dog May Have Heartworm Disease

One of the most serious and potentially life-threatening conditions in dogs is heartworm disease. This issue can affect dogs of all breeds, sizes, and ages. Parasitic worms get into your dog through mosquito bites. Detecting this condition early on is the best way to keep your dog healthy since heartworm disease progresses in stages. If you notice these signs your dog may have heartworm disease, you should take them to a vet to discuss treatment options before their condition gets worse.

1. Persistent Coughing

An early and common sign of heartworm disease is a persistent, dry cough. The coughing is because your dog has irritated lungs, as this is where the heartworms often nestle to grow. While dogs may also cough from seasonal allergies or other throat irritation, a cough that comes from heartworms usually won’t go away on its own and persists over time.

If you notice your dog coughing at a regular, alarming level, it’s time to get in touch with your vet. Some dogs also have a slight wheeze while they breathe, which could be a respiratory issue. That said, it’s not a symptom you want to ignore.

2. Reduced Exercise Tolerance

Dogs with heartworm disease may show a sudden decrease in their ability to handle physical activity. Does your dog normally love to run or go on long walks but suddenly needs to stop and rest more than usual? You may notice this symptom gets worse as your dog’s condition progresses since exercise puts a lot of strain on your dog’s heart and lungs. Even simple activities like climbing the stairs or rushing to grab a toy may lead to surprising fatigue.

3. Lethargy and Weakness

Another clear indicator of heartworm disease is lethargy. If your dog normally has a lot of energy but is now spending a lot more time sleeping or avoiding interacting with you, this may be due to their heart having to work harder to pump blood. All that extra cardiac effort leaves your dog feeling weak and exhausted.

4. Rapid or Labored Breathing

Dogs with heartworm disease often experience changes in their breathing patterns. Some symptoms include rapid, shallow breathing or a noticeable struggle to catch their breath, even when at rest. As heartworm disease develops, the worms can obstruct blood flow and put a lot more pressure on the lungs. Determine if your dog is struggling to breathe, especially if it seems to be an issue when they’re not engaging in heavy activity, and schedule a vet appointment.

5. Loss of Appetite

Dogs with heartworm disease may lose their interest in food and treats. Although a reduced appetite is a common secondary symptom of many illnesses, it’s a regular side effect of heartworm disease. The loss of appetite comes from a combination of discomfort, fatigue, and the general strain on the dog’s internal organs. Appetite loss can contribute to further health complications, such as unintended weight loss and muscle weakness.

6. Unexplained Weight Loss

Another sign your dog may have heartworm disease is if they experience sudden weight loss. Even if your dog hasn’t had a loss of appetite, if they’re still losing weight, it may stem from the internal strain of the disease. Heartworm disease requires your dog’s body to work harder to fight off parasites, burning more calories. Noticing a thinner physique or a reduction in muscle mass is a red flag that warrants veterinary attention.

7. Swollen Belly or Fluid Retention

One of the more noticeable visual symptoms of heartworm disease in dogs is abdominal swelling, also known as ascites. Since heartworms compromise your dog’s heart and impede its ability to function properly, your dog develops fluid retention and a swollen gut. You can clearly see this symptom, as your dog will have a rounded or bloated belly. While dogs may experience this stomach distention from other causes, seeing it alongside the other symptoms on this list should raise immediate concerns.

8. Pale or Discolored Gums

Dogs with heartworm disease may have pale or discolored gums that stem from interference with proper blood flow. The disease reduces the oxygen levels in your dog’s body, negatively affecting their oral health. Reduced oxygen results in a lighter or bluish hue in the gums or tongue instead of a healthy pink color. Noticing discolored gums alongside any of the other symptoms discussed should warrant an immediate evaluation from a veterinarian.

9. Fainting or Collapsing

Fainting or sudden collapse, also known as syncope, is one of the more severe symptoms associated with heartworm disease. Syncope occurs because restricted blood flow prevents oxygen from reaching critical parts of the body, like the brain. It’s most common for your dog to faint or collapse after physical activity due to the lung or heart issues caused by heartworm disease. This symptom indicates the disease is at a more advanced stage and thus warrants immediate medical attention.

Prevention Is Key to Protecting Your Dog

Early detection is essential to manage heartworm disease effectively in dogs. Regular veterinary checkups and annual heartworm tests can detect the disease before symptoms become severe. If you suspect your dog may be showing signs of heartworm disease, consult your veterinarian as soon as possible. They can perform the necessary diagnostic tests and recommend the best treatment plan based on your dog’s specific needs.

Preventing heartworm disease is always easier, safer, and less expensive than treating it. Monthly preventative medications, paired with consistent veterinary monitoring, can protect your dog from heartworm infections. Living in an area with a high mosquito population increases your dog’s risk, so don’t underestimate the importance of year-round protection.

If you’re concerned about your pet’s health or need immediate assistance, The Complete Pet Animal Hospital is here to help. Our dedicated team offers comprehensive care, including emergency pet services, so your furry friend receives the attention they need when it matters most.