Top Signs & Symptoms That Your Dog May Have Heartworms

Top Signs & Symptoms That Your Dog May Have Heartworms

Top Signs & Symptoms That Your Dog May Have Heartworms

Top Signs & Symptoms That Your Dog May Have Heartworms


The American Heartworm Society defines heartworm disease as a severe, and possibly deadly, disease in pets. It is widespread in the United States and numerous countries. This disease is caused by an infestation of worms measuring a foot long each that go straight to the lungs, heart, and blood vessels. Heartworms seem to infest all mammals, but it is more heartbreaking when the disease affects your pet. If you want to find out the signs and symptoms of heartworms in dogs, here’s what you should know.

Difficult or Rapid Breathing


Your dog may already have some breathing difficulties. Problems in respiration usually happen when the worms start to collect in the lungs and surrounding blood vessels. Heartworms may also result in fluid buildup in the blood vessels inside the lungs. Once there is fluid buildup in the lungs, it is difficult for the lungs to oxygenate the blood.




If your dog seems to be tired all the time and avoids any physical activity, it may have heartworm disease. This is because of the poor pumping action of the heart and inadequate oxygenation of the blood. Your dog may even find it too tedious to get up to eat, drink, or even come to you when you call. It can be alarming when this happens.


Soft and Dry Cough


Difficulty in breathing often accompanies coughing in dogs with heartworm disease. The worms start multiplying in the dog’s lungs and the veins surrounding it. You may notice your dog coughing after exercising. The episode may end with your dog fainting even after light exercise.



Heartworm disease can also trigger some allergic reactions. Though it is more common in felines, some dogs can manifest symptoms that are similar to allergies. Your dog’s symptoms also may appear similar to an asthma attack, which may be your dog’s reaction to adult heartworms, immature worms, or eggs.

Weight Loss


When your dog does not want to move, even to eat or drink, it will lose weight. The weight loss may happen quickly because of your dog’s inability to take in the right amount of nutrients. It may already be suffering from muscle wasting as well. You should bring your dog to the vet right away if you notice some weight loss and dehydration.



Mature heartworms migrate to the heart and block the flow of blood, which is known as vena cava, or caval, syndrome. When this happens, your dog will experience a sudden collapse, which usually comes with the destruction of red blood cells and shock. This is the late stage of the disease and usually results in death within days.

Protruding Chest


This usually shows in the dog’s ribs. If your dog’s ribs and chest area are protruding, this is a telltale sign of heartworm infestation. There will be weight loss as well. The chest and rib protrusion might be a result of fluid buildup, and it is an allergic response to the parasite’s presence in your dog’s body.

Heartworm is a life-threatening disease in dogs. Other symptoms are blindness, nosebleeds, secondary pneumonia, lameness, high blood pressure, and seizures. At Port Royal Veterinary Hospital, we encourage our pet parents to bring in their fur babies for regular checkups. That way, we can detect and treat any disease early. You can visit our clinic in Port Royal, South Carolina, for an in-person consultation. Please call us at 843-379-7387 for appointment scheduling or inquiries about our heartworm treatment packages.