Yes, both dogs and cats can get lice, though it’s far less common than fleas or ticks. Lice are flat, wingless, six-legged insects visible to the naked eye that spend their entire 21-day life cycle on the animal. They’re uncommon enough that many pet owners never encounter them, but infestations do happen, particularly in animals with poor grooming or crowded living conditions.
Dogs and Cats Get Different Lice
Lice are strictly host-specific, meaning each species of louse can only survive on one type of animal. Dog lice infect dogs. Cat lice infect cats. Human lice infect humans. A dog or cat louse might occasionally end up on a person, but it won’t stay, feed, or reproduce there. This also means your dog can’t give lice to your cat, or vice versa.
Dogs can be affected by two types of lice: chewing lice that feed on skin debris and sucking lice that feed on blood. Cats have it simpler. Only one louse species affects them, and it’s a chewing (biting) type. Because cat lice feed on skin and hair debris rather than blood, heavy infestations in cats tend to cause intense skin irritation but are less likely to lead to anemia compared to the sucking lice that can affect dogs.
How Common Are Lice in Pets?
Lice are the least common of the “big three” external parasites in pets. In one large veterinary survey, fleas were found on nearly 70% of dogs examined and about 22% of cats, while ticks appeared on roughly 37% of dogs. Lice, by contrast, showed up in under 5% of dogs and were completely absent in the cats sampled. Modern flea and tick preventatives that many pet owners already use tend to kill lice as well, which likely keeps prevalence low in well-cared-for pets.
Lice infestations are most often seen in young, elderly, or debilitated animals, as well as pets living in overcrowded or unsanitary conditions. Stray and shelter animals are at higher risk than pets receiving routine parasite prevention.
How Lice Spread Between Animals
Lice spread almost exclusively through direct contact between animals. Unlike fleas, which jump, lice don’t move much or quickly. They crawl from one host to another when animals are in close, sustained contact. Shared bedding, grooming tools, and collars can theoretically transfer lice or their eggs, but this is a secondary route. Lice that fall off an animal die within a few days, and their survival off the host is limited to two to three days at most.
Eggs (called nits) are a different story. Nits are glued to individual hairs and can continue hatching for two to three weeks after being separated from the host. This is why cleaning bedding and grooming tools matters even after you’ve treated the animal itself.
Signs Your Pet Has Lice
The most obvious sign is persistent scratching, biting, or rubbing at the skin. An infested pet’s coat often looks rough, dry, and matted. Hair loss can develop in areas where the animal has been scratching heavily. In severe cases, particularly with sucking lice on dogs, the blood loss can cause anemia, which shows up as pale gums, lethargy, and weakness.
Lice can be harder to spot in long-haired breeds. You may need to part the fur and look closely at the skin, especially around the ears, neck, and shoulders. Adult lice appear as small, flat, light brown or tan insects clinging to hair shafts. Nits look like tiny white or yellowish dots cemented to individual hairs near the skin surface, similar in appearance to dandruff but impossible to flick off easily. Unlike dandruff, nits are firmly attached and won’t shake loose.
Treatment and Cleanup
Lice infestations are straightforward to treat. Many of the same topical parasite preventatives used for fleas and ticks are effective against lice. Your vet can recommend the right product for your pet’s species and size. Treatment typically needs to be repeated or continued for several weeks to kill lice that hatch from surviving nits after the initial application, since most products kill adult lice but don’t destroy eggs.
Severely matted coats sometimes need to be clipped to remove large numbers of nits and allow treatment to reach the skin. If multiple pets of the same species share a household, all of them should be treated simultaneously, even if only one is showing symptoms.
On the environmental side, wash all bedding in hot, soapy water and clean or replace grooming tools, collars, and harnesses. Repeat this cleaning regularly until the infestation is fully resolved. Because lice die within days off the host and nits can hatch for up to three weeks, continuing environmental cleanup for at least three weeks after starting treatment helps prevent reinfestation.
Lice vs. Fleas: Key Differences
- Movement: Fleas jump rapidly between hosts and throughout your home. Lice crawl slowly and rarely leave the animal.
- Survival off the host: Flea larvae can survive in carpets and furniture for weeks or months. Lice die within two to three days off the animal.
- Host specificity: Cat fleas readily bite dogs, cats, and humans. Lice can only survive on their specific host species.
- Visibility: Both adult fleas and lice are visible to the naked eye, but lice tend to stay put when you part the fur, making them easier to spot. Fleas scatter quickly.
- Home infestation: Fleas can take over your house. Lice cannot establish themselves in your carpets or furniture because they need constant contact with a host to survive.
If your child has head lice, the family dog or cat is not involved. Children get lice exclusively from other humans through head-to-head contact. Your pets cannot serve as a reservoir for human lice, and you cannot catch lice from your pets.