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What are the Symptoms of Parasites in Dogs?

Susana Bradford
January 12, 2024
5 minutes read
Updated By
Expert Reviewed By:
August 29, 2023
5 minutes read
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The symptoms of parasites in dogs depend on the type of parasite. Dogs with skin parasites typically have hair loss, while those...

The symptoms of parasites in dogs largely depend on what type of parasite the dog has. Skin parasites in dogs include fleas, ticks, and mites, with signs such as scratching, biting on the skin, and hair loss. 

Hookworms, tapeworms, and whipworms are intestinal parasites that can cause gastrointestinal discomfort, blood in the feces, and abdominal distension.

Heartworms may not show symptoms until the parasite load is high enough to cause heart damage. At this point, the symptoms likely include coughing and bloody coughing.

How Do Parasites Affect Dog’s Skin?

Dog owners are most likely to see parasites in their pet’s skin, often known as skin parasites. Many dog owners will not have to wait for symptoms of fleas or ticks because the parasites will be visible in their pet's fur. Mites, however, cannot be seen with the naked eye.

Skin parasites in dogs can cause the dog to constantly lick at its coat, develop skin lesions, and have crusty sores on the skin. If mites penetrate a dog's ears, symptoms may include ear discharge, ear scratching, and head shaking.

In the case of a tick bite, symptoms may include a rash and swelling at the site of the bite. Sometimes, a pet can develop anemia and more serious symptoms if a skin parasite infection is severe.

The following are symptoms of various skin parasites:


Fleas are tiny parasites that live on a dog’s fur. Flea dirt is one of the most obvious signs that your ESA dog has a flea infestation. Flea dirt is the parasite's undigested blood waste.

If a dog has a lot of fleas, there will be flea dirt everywhere the animal sits or sleeps. It will also show up on the floor or table under the dog after brushing or combing. Flea dirt looks like black powder.

Other signs that your emotional support animal might have fleas include:

  • Scratching
  • Wounds 
  • Alopecia
  • Anemia


These are tiny parasites that suck a dog’s blood. They cause itchiness and cause dry and flaky skin. In extreme cases, lice can cause anemia.


Ringworms are fungi that dwell in a dog's hair, skin, and nails. Inflammation of the skin, dry and brittle nails, and irritated skin are all classic signs of a ringworm infection.

Your veterinarian may prescribe oral medication and topical creams to treat ringworm infection.

How Do Intestinal Parasites Affect Dogs?

There are a couple of intestinal parasites that dog owners may see. Tapeworms and roundworms are visible in feces or vomit, but other types of intestinal parasites can only be detected by a fecal examination.

Additional symptoms of intestinal parasites in dogs include diarrhea, nausea, and vomiting. 

If a dog has a significant load of intestinal parasites, or if the dog is a young puppy or an elderly dog, symptoms such as weakness, loss of appetite, and severe weight loss may occur. Puppies with a significant load of intestinal parasites typically have a swollen abdomen.

The following are symptoms of different intestinal parasites:


Roundworms are intestinal worms. Toxocara canis is a common type of roundworm that mainly affects puppies. In most cases, puppies are born with these parasites. So, you should ensure that your newborn puppies receive proper veterinary care.

Roundworms are easily detected using fecal samples. If not treated on time, these parasites can cause stunted growth and, in severe cases, death.


These are intestinal parasites that commonly infect flea-infested dogs. Tapeworms can infect a dog that consumes fleas or tapeworms from wild animals. The most common type of tapeworm that affects dogs in the United States is Dipylidium caninum

The presence of tapeworm segments in a dog's tools is the most typical indicator of a tapeworm infection. The segments resemble rice grains. If your dog has tapeworms, it is usual for it to scoot its back along the ground.

While a veterinarian will administer oral or injectable medication to a dog with tapeworms, you should check your home for fleas and eliminate them.


Hookworms are intestinal worms linked to anemia, particularly in pups. When these parasites adhere to the intestinal wall of your emotional support animal, they suck significant quantities of blood.

Dogs commonly acquire hookworms by consuming hookworm larvae found in the environment. This parasite is sometimes passed to puppies through the mother dog's breast milk.

A veterinarian uses the fecal flotation technique to diagnose hookworms. If you have an ESA letter, your vet will give the dog deworming medication.


Whipworms are parasites found in the cecum, the first section of the large intestine. A dog can contract whipworms by eating dirt, food, water, or feces containing the parasite. 

In moderate situations, these parasites cause almost no symptoms. However, severe cases might cause inflammation, anemia, weight loss, and diarrhea. Your veterinarian will need a stool sample to diagnose whipworms.

A veterinarian may miss whipworm eggs in feces, resulting in false negatives. Therefore, you should conduct multiple tests if your dog's stool contains blood stains.


Heartworms are parasites that dwell in the heart. They have been associated with lung disease, heart failure, organ damage, and in rare cases, death. These worms, according to experts, are common along the Atlantic and Gulf coasts of the United States.

Heartworm treatment is time-consuming, costly, and may result in death. As a result, it is best to protect your dog from these parasites. Heartworm treatments also often involve the confinement of the ESA dog, which can be stressful for the dog and the owner.


Intestinal flukes

Intestinal flukes only lead to symptoms if they are in large numbers. When this happens, they lead to intestinal inflammation. You can easily treat intestinal flukes using different types of antiparasitic medications.

Liver flukes

These flukes dwell in the dog's bile ducts and gallbladder and cause fibrosis, a type of liver disease. Mild infections produce almost no symptoms. In severe cases, dogs may show weakness, fatigue, and even die.


This parasite is commonly found in pups. It attaches itself to a dog’s intestine after the dog ingests infected soil. A dog with coccidia parasites usually has watery diarrhea and vomits. In severe situations, oral medicine is recommended in addition to IVs.


Giardia is commonly found in older dogs that consume contaminated water. There are no distinctive symptoms associated with a giardia infection. So, keep an eye out for common parasite symptoms such as diarrhea and vomiting.

Keeping Your Dog Healthy and Avoiding Parasites

The best way to protect your dog against parasites is through prevention, regular testing, and good cleanliness.

Visit Pettable's blog for pet care information, ESA certification, and other helpful resources.

Meet the author:
Susana Bradford

Susana is an avid animal lover and has been around animals her entire life, and has volunteered at several different animal shelters in Southern California. She has a loving family at home that consists of her husband, son, two dogs, and one cat. She enjoys trying new Italian recipes, playing piano, making pottery, and outdoor hiking with her family and dogs in her spare time.

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