What are the Symptoms of Parasites in Dogs?

Bethney Foster

The symptoms of parasites in dogs are largely dependent upon what type of parasite the dog has. Skin parasites in dogs include fleas, ticks, and mites, with symptoms such as scratching, biting at the skin, and hair loss. Intestinal parasites, such as hookworms, tapeworms, and whipworms, may be accompanied by gastrointestinal symptoms, blood in the feces, and abdominal distension. Heartworms may create no symptoms until the parasite load is heavy enough to start damaging the heart. At this point, the symptoms will likely be coughing and coughing up blood.

Vets use ear drops to treat a dog with ear mites.
Vets use ear drops to treat a dog with ear mites.

Parasites in dogs' skin, or topical parasites, are those that dog owners are most likely to see. Many dog owners will not have to wait for symptoms in the case of fleas or ticks, but will see the parasites in their pet’s fur. Mites will not be visible to the naked eye.

A brown dog tick.
A brown dog tick.

With a flea infestation, a primary symptom is the presence of flea dirt. Flea dirt is the parasite’s excrement of undigested blood. If a dog has a substantial flea infestation, flea dirt can be seen anywhere the pet sits or sleeps for any length of time. It will also be visible on the floor or table beneath the dog any time the dog is combed or brushed. Flea dirt looks like black powder.

Other symptoms of skin parasites in dogs are the dog continually licking at its coat, the development of skin lesions, and crusty sores on the dog’s skin. If mites get into the dog’s ears, symptoms may include discharge from the ears as well as the dog frequently scratching the ears and shaking its head. In the case of tick bite, symptoms may include a rash and swelling at the site of the bite. In some instances, if a topical parasite infection is severe, a pet can develop anemia and more serious symptoms.

There are a couple of intestinal parasites that dog owners may actually see. Tapeworms and roundworms are visible in the stool or vomit, while other types of intestinal parasites will need to be diagnosed by a fecal examination from a veterinarian. Additional symptoms of intestinal parasites in dogs include diarrhea, nausea, and vomiting. If a dog has a heavy load of intestinal parasites or if the dog is a young puppy or elderly dog, symptoms may become more serious and include weakness, loss of appetite, and severe weight loss. Puppies often have a bloated abdomen if they have a heavy load of intestinal parasites.

A dog constantly scratching might have a skin parasite infection.
A dog constantly scratching might have a skin parasite infection.

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Discussion Comments

@SarahGen-- You might not see a complete worm in the stool, but you will certainly see pieces of the worm from time to time. These pieces usually look like rice. Sometimes you can even find them in the dog's bed.

Like the article described though, every type of intestinal worm in dogs will cause some sort of gastrointestinal disturbance. So that's the first thing to look out for.


I don't think tapeworms and roundworms in dogs are visible in the stool unless anti-parasitic drugs have killed them and caused them to be removed with stool.

I had a dog that had a roundworm infection for years. I never knew about it until the vet recommended annual anti-parasitic shots as a precaution because we moved to a farm. As the parasites died, that's when I started seeing them in his stool.


Fleas and ticks are fairly easy to notice. Ticks usually attach to skin where the fur is short, like the head or stomach of the dog. Fleas are more difficult to see, especially in dogs that are black or brown, but itching gives them away.

Once my dog had such a terrible flea infestation that I could see the parasites jumping all over him.

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