What are External Parasites in Dogs?
What is it?
How is it Treated?
Breed Predispositions
There is no specific breed predisposition to external parasites in dogs. However, factors such as lifestyle, exposure to outdoor environments, and poor hygiene can increase the risk of external parasite infestations.
Introduction
Amanda had always enjoyed the bond she shared with her lively Australian Shepherd, Luna, frequently taking her on outdoor adventures through the woods and along the beach. One day, as they returned from a particularly exciting hike, Amanda noticed Luna incessantly scratching and biting her fur. Concerned, she decided to give her a thorough inspection and was shocked to discover small, unwelcome guests hiding among Luna’s beautiful coat: external parasites. In this blog post, we will delve into the world of external parasites in dogs, discussing the various types, symptoms, treatments, and preventative measures. As you read on, you’ll gain the knowledge necessary to protect your canine companion from these pesky invaders, ensuring they can continue to enjoy their outdoor escapades while remaining happy and healthy.
Parasites are organisms that live inside another organism without harming it. They feed on the host’s blood, tissue, or fluid. Many parasites are harmless, but some are dangerous and even fatal. Examples of external parasites in dogs include fleas, ticks, mites, lice, etc. These parasites can cause serious health issues and discomfort for your dog if they are not cared for properly.
It is essential to regularly check your pet for signs of external parasites and seek treatment if necessary by consulting with your veterinarian for diagnosis, prevention and treatment options.
Types of External Parasites in Dogs
Many external parasites exist, including fleas, ticks, mites, and lice. Fleas are tiny insects that bite dogs and spread disease. Ticks are giant arachnids that feed on blood. Mites are tiny creatures that burrow into the skin and suck out fluids. Finally, lice are wingless insects that attach to hair follicles and suck blood.
Fleas
Flea infestation is one of the most common problems pet owners face today. These tiny insects feed off the blood of pets and humans. They are easily spread among animals via contact with each other, contaminated bedding, clothing, toys, etc. Fleas and ticks cause irritation, itching, scratching, hair loss, skin rash, and even secondary infections such as ringworm. In addition, dogs and cats can contract diseases like tapeworms, heartworms, mange mites, eye disorders, and kidney disease.
Tick Infestations
Types of tick species are tiny arachnids that live on wild animals and domestic livestock. They carry bacteria that cause Lyme Disease, Rocky Mountain Spotted Fever, Ehrlichiosis, Tularemia, and Babesiosis. In addition to being vectors for infectious agents, ticks transmit bacterial pathogens that cause tick paralysis, tularemia, Colorado Tick Fever, and anaplasmosis.
Lice
Different types of lice parasitic insects attach themselves to the skin, face, body, and pubic areas. They suck blood, causing intense itching and discomfort. Their eggs are passed onto the next host during close contact. Lice are usually associated with poor hygiene and unkempt appearance.
Demodex Mites
Demodex mites are prevalent in dogs but rarely seen in humans. They live in the hair follicles of animals and feed off dead skin cells. They are found in nearly every dog. However, most cases occur between 4 months and eight years. Stressful situations like boarding kennels or being left alone without food or water can cause a dog to become ill and shed their coat. This allows the mite population to increase.
Ear Mites
Ear mite infestations are usually transmitted through close physical contact. For example, a dog rubbing against another animal or a human may pick up the parasite. If you notice that one of your pets has ear infections, it could mean they have ear mites. Regular ear cleaning can help prevent your dogs from getting ear mites.
Sarcoptes
Sarcoptes scabiei is the most common species of Sarcoptes responsible for sarcoptic mange. They are highly contagious, worm-like parasites that cause deep skin lesions. The parasite lives in the hair follicles and causes inflammation and thick scales that may push out surrounding hair. It can be spread through contact with infected animals or their excrement, although it’s more commonly contracted by scratching or rubbing affected areas. Symptoms typically develop within three weeks after exposure and can wax and wane over time, but they generally last between six to 12 months.
Causes of External Parasites in Dogs
There are many reasons why dogs develop internal parasites. Commonalities include poor nutrition, stress, lack of exercise, overpopulation, and improper grooming. But there are some things we still need to understand.
One of those things is why certain breeds seem prone to developing external parasites that can cause extreme pain to young dogs. This often happens with German Shepherds, Golden Retrievers, Labradors, and Boxers.
We’re not saying these breeds are inherently wrong; instead, we’re simply pointing out that it spreads quickly through the entire population when they encounter a parasite infestation. And because of this, we recommend keeping your dog away from other animals until they are entirely parasite-free.

Clinical Signs of External Dog Parasites
Dogs may be infected with worms, fleas, ticks, or tapeworms. The most common parasite found in dogs is a roundworm (Toxocara), followed by hookworms, whipworms, and heartworms.
Symptoms may vary depending on the type of parasite and where it lives. Flea bites usually cause itching and scratching. Ear mite infestations result in painful ears. Ticks transmit Lyme disease; Rocky Mountain spotted fever, anaplasmosis, babesiosis, and ehrlichiosis—hookworms cause diarrhea and malnutrition. Roundworms produce worms that grow inside the intestines. Tapeworms cause intestinal blockage. Whipworms cause severe abdominal pain. Heartworm causes congestive heart failure.
Other symptoms include vomiting, weight loss, lethargy, coughing, sneezing, and skin allergies. In addition, some dogs develop liver disease, intestinal blockage, seizures, blindness, paralysis, or kidney failure.
If you suspect your dog has an infection, immediately take him to the vet. Your veterinarian will perform a thorough examination and test for parasites. They will also recommend appropriate treatments.
Diagnosis of External Parasites in Dogs
Vets diagnose external parasites such as fleas, mites and ticks in dogs by conducting physical examinations to assess for any signs and symptoms of possible infestation. They will use a comb to check for any visible parasites on the pet’s fur or skin and look for evidence of damaged hair follicles, redness or irritation on the skin that could suggest an infestation.
Vets may also take samples of the pet’s fur or skin scrapings to examine under a microscope for visible eggs, larvae, and adult parasites. They may also use an ELISA test – a measuring technique that detects clues suggesting parasite presence within the pet’s body.
To confirm an infestation of external parasites, vets may do an antigen-antibody test using blood to detect antibodies that are present if a dog has been exposed to certain types of parasites. This test can provide accurate results on the species and varieties of parasites in your dog’s system.
Once external parasites are confirmed with diagnostic tests, vets can begin treatment options such as topical ointments, spot treatments or oral medications depending on the severity and species/type of parasite identified during testing. Owners must comply with their vet’s recommended treatment guidelines to ensure that all external parasite infestations have been eliminated from their pet’s body.
Treatment for External Parasites in Dogs

Treating these parasites is essential because they can cause serious health problems. For example, fleas can transmit tapeworms, leading to liver disease. Ticks can carry Lyme disease. Lice can spread heartworm disease. In addition, worms can cause intestinal blockages.
If you suspect your pet may be infected with these parasites, immediately take them to the vet. The sooner treatment begins, the better off your pet will be.
Vets usually recommend treating external parasites with home remedies and prescription drugs. However, some pets may need stronger medications.
Here are some common treatments for external parasites in dogs:
- Flea collars – These work well when used correctly. The collar should be applied at night, and the pet must wear it until the fleas die off naturally (usually within two weeks).
- Shampoo – This works well, too, especially if combined with a flea collar.
- Medicated shampoos – Some medicated shampoos contain permethrin, which kills fleas and ticks. Be careful not to use these shampoos near children or animals because they can harm them.
- Spay/neuter – Many veterinarians recommend spaying or neutering outdoor pets. This prevents unwanted puppies and kittens from being born.
- Antifungal shampoo – Antifungal shampoo helps prevent ringworm. Ringworm is a fungus that causes red patches on the dog’s skin.
- Parasite drops – These drops help control internal parasites in dogs. Internal parasites include roundworms, hookworms, whipworms, tapeworms, and giardia.
- Worming tablets – These pills kill worms inside the body.
- Anti–inflammatory topical ointments – Ointments containing anti-inflammatories relieve pain and itchiness associated with external parasites.
- Insect repellent – Pet owners often apply insect repellents to protect their pets against insects.
- Bedding – Bedding made from natural fibers, such as wool, cotton, or silk, reduces the risk of getting external parasites.
- Bathing removes dirt and debris from the coat, reducing the chances of getting external parasites.
External Parasites Prevention in Dogs
Preventative measures are typically used to control internal parasites in dogs, while topical treatments are usually reserved for external ones. Both methods are effective, but each has advantages and disadvantages.
Prevention is generally recommended over topical treatments. While topical treatments can kill parasites, they aren’t always 100% effective. Fleas, for example, can survive off of a dead host for weeks after treatment. Prevention is much easier to maintain, preventing heavy flea infestations that may lead to severe skin disease.
The first thing you need to do is wash your hands thoroughly after handling your pet. Make sure to clean under his nails and inside his ears. Then, brush him regularly to remove dead skin cells and hairballs. Finally, bathe him frequently to remove dirt and debris.
Next, look for signs of internal parasites. These are usually easier to spot than external ones since they tend to manifest themselves in different ways. Some common symptoms include diarrhea, vomiting, and weight loss.
To prevent internal parasites, feed your dog a healthy diet. For example, avoid feeding him foods that contain raw meat, bones, or dairy products. Also, avoid giving him treats, including chocolate, raisins, grapes, onions, garlic, or caffeine.
Lastly, watch out for fleas. Fleas love warm weather, so keep your house cool during summer.
Please keep your dog indoors whenever possible, and apply insect repellent to his coat.
Be sure to consult your veterinarian if you notice any unusual behavior. He can perform blood tests to detect diseases caused by parasites.
Both prevention and topical treatments are safe and easy to administer. Follow label instructions closely and watch for signs of allergic reactions. Ensure you wash your hands thoroughly after applying anything to your dog’s body.
Frequently Asked Questions
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