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.
But there is plenty of bad news where this parasite is concerned. Like the more common pest for dogs — fleas — a louse infestation, which is known by the scientific term pediculosis (from the Latin word for louse, which is “pediculus”), 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 pet is unlucky enough to pick them up.
What Are Dog Lice?
Dog lice 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 survive by eating skin debris and surface secretions and are characterized by 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 is found mostly in tropical regions, and although rare on dogs in North America, has been seen on the coyote, red fox, and gray wolf. Researchers have also discovered this type of lice on dogs in southeastern Mexico in a study in 2015.
- 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 are widespread in tropical and subtropical areas of North and South America, Africa, India, and Asia.
What Are the Signs of Dog Lice?
You can see the parasite itself by parting the dog’s hair and examining the hair shaft. Adult lice are large enough to be visible to the naked eye, roughly the size of a sesame seed — about 2-to-4 millimeters — and are yellow to tan or medium brown in color. They are distinguishable from fleas, which are very dark, almost black looking.
Chewing lice will move around more than the 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.
Lice, especially the eggs or nits, are sometimes mistaken for dandruff, and 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.
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, although 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, dog shows, boarding kennels, and parks.
There are three stages to the louse life cycle:
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. The Merck Veterinary Manual says it takes about 3-to-4 weeks for most lice to go from nit to reproductively capable adult.
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.
To start, treatment in severe 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. (After you use it, be sure to immerse the comb for at least 10 minutes in water mixed with a flea shampoo or other insecticide.) However, a flea comb won’t kill the eggs that are on the dog or prevent them from hatching.
Many insecticides are effective treatments for lice in dogs. According to the Companion Animal Parasite Council (CAPC), Fipronil, imidacloprid, and selamectin are all effective. Topical permethrin can be used on dogs with good effect.
Dr. Jerry Klein, AKC chief veterinary officer, warns that it is important to be careful about using some of these products if you own cats as well as dogs, because they are toxic to cats. “And always ask your veterinarian about what products are safe to use on your dog based on his health, breed, and age,” he says.
Insecticide treatments given topically or in shampoos will kill nymphs and adults, but will not eradicate the eggs, so any treatment will have to be repeated at regular intervals for one month or more. All dogs in the household should be treated. Be sure to keep an infested dog and his 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 replacing your grooming tools because it can be difficult to remove the sticky eggs from combs and brushes.
Lice generally attack dogs who are in poor health or who 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.