Lice on Dogs: Signs, Symptoms, Treatments

If your dog or a member of your family has lice, you may be concerned about how this parasite spreads. First, the good news: You cannot get lice from your dog, nor can your dog pick up this parasite from you. Lice are species-specific; those that thrive on your dog’s blood won’t change their dining preferences if they land on you, or vice versa.

However, there’s plenty of bad news where this parasite is concerned. Like fleas, the more common pest for dogs, a lice infestation can cause itching, pain, inflammation, and hair loss. It can also lead to more serious health issues, so it’s important to learn how to recognize and quickly eradicate lice if your dog is unlucky enough to pick them up.

What Are Dog Lice?

Lice that infest dogs are small, flat, wingless, six-legged insects that live in the hair and feathers of mammals and birds. Strong hook-like claws at the end of each leg allow them to hang onto the animal’s hair shafts. The claws are tailored to the specific size of the host’s hair shaft or feathers, which is why lice are species-specific. They survive on skin debris, sebaceous secretions, feathers, or the blood of the host animal.

There are two types of lice:

Chewing Lice

Chewing lice survive by eating skin debris and surface secretions and have a blunt, flat head.

There are two species of chewing lice that affect dogs and wild canids — Trichodectes canis and Heterodoxus spiniger. T. canis is found worldwide and typically lives on a host for 30 days. H. spiniger mostly appears in tropical regions. Although it’s rare on dogs in North America, it’s been seen on the coyote, red fox, and gray wolf. Researchers also discovered this type of lice on dogs in southeastern Mexico in 2015.

Sucking Lice

Sucking lice need blood to survive. The species of sucking lice that affects dogs is called Linognathus setosus. Unlike the chewing lice, these have a sharp pointed mouthpiece. They’re widespread in tropical and subtropical areas of North and South America, Africa, India, and Asia.

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What Are the Signs of Dog Lice?

Adult lice are large enough to be visible to the naked eye, roughly the size of a sesame seed (about 2-to-4 millimeters). These parasites are yellow to tan or medium brown in color. You can see the parasite itself by parting the dog’s hair and examining the hair shaft.  They’re distinguishable from fleas, which are very dark and almost black looking.

Chewing lice will move around more than sucking lice, which, like ticks, embed their piercing mouthparts into the skin. If you suspect an infestation of dog lice, you might want to go over the area with a flea comb and examine the hair.

Dog owners sometimes mistake lice, especially the eggs or nits, for dandruff. One way to distinguish lice from dandruff is by shaking hair removed from the dog. If the small flakes fall off, it’s dandruff. If they cling stubbornly to the hair, it’s probably lice. Other signs of lice infestations on your dog include:

• Scratching and intense itchiness
• Rough, dry, or matted coat
• Hair loss, specifically around ears, neck, shoulders, groin, and rectal regions
• Small wounds or bacterial infections from bites by sucking lice
• Restless behavior
• Anemia in extreme cases, or in small dogs and puppies
• Tapeworms and other bacteria or parasites that are spread by lice

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How Do Dogs Get Dog Lice?

Lice have limited mobility. They can crawl, but are unable to jump, hop, or fly. Also, adult lice die in a few days if they fall off the host. Transmission is usually through direct contact with another infested animal. However, they can also be passed on from contaminated bedding, dog collars, or grooming tools. Lice may be a threat wherever dogs congregate, such as dog daycare centers, boarding kennels, and parks.

There are three stages to the louse life cycle: egg, nymph, and adult.

The cycle starts when the female lays tiny yellow or white eggs at the base of the hair shaft. These eggs are glued to the hair and won’t fall off when the dog is shampooed.

It takes about one week for the eggs to hatch, releasing the immature lice, known as nymphs, which are no larger than the head of a pin. After about one week, they enter the adult phase, starting the cycle all over again. According to the Merck Veterinary Manual, it takes about 3-to-4 weeks for most lice to go from nits to reproductively capable adults.

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How Do You Get Rid Of Dog Lice?

Monthly flea and tick preventives have made lice infestations rare among well-cared for pet dogs. Today, lice are found mostly on animals that are old, sick, stray, or feral.

Treatment of severe lice infestations involves clipping matted hair off the dog because lice and eggs will likely be attached to that hair and hard to dislodge. You can also use flea combs to remove live and dead lice on the rest of the coat. However, a flea comb won’t kill the eggs that are on the dog or prevent them from hatching. Note: after you use a flea comb, be sure to immerse it in water mixed with a flea shampoo or other insecticide for at least 10 minutes.

Many insecticides, such as Fipronil, imidacloprid, and selamectin, are effective treatments for lice in dogs. Topical permethrin can also be used on dogs with good effect. “Always ask your veterinarian about what products are safe to use on your dog based on his health, breed, and age,” says Dr. Jerry Klein, AKC Chief Veterinarian. It’s also important to be careful about using some of these products if you own cats as well as dogs, because many are toxic to cats.

Insecticide treatments given topically or in shampoos will kill nymphs and adults, but won’t eradicate the eggs. You must repeat any treatment at regular intervals for one month or more. If you have a multi-dog household, be sure to treat all of your dogs. Be sure to keep an infested dog and their bedding away from other animals for at least four weeks after treatment.

Make sure you wash all bedding, dog sweaters, leashes, and collars in hot water and thoroughly clean all areas where the dogs spend time to prevent a reinfestation. Some veterinarians recommend also replacing your grooming tools because it can be difficult to remove the sticky eggs from combs and brushes.

Lice generally infest dogs who are in poor health or live in unsanitary areas. Improving the dog’s condition through better nutrition, grooming, and housing, will go a long way toward preventing future louse infestations.