Lice in Dogs

Causes, Treatment, and Prevention

Dog in grass itching behind its ear

Nick Ridley / Getty Images

Lice are dreaded by parents of both pets and kids because these parasites cause severe itching and can be tough to eradicate. Untreated lice infestations in dogs can lead to skin infections and bald patches caused by excessive scratching. Lice are relatively rare among dogs in the United States, but infestations do happen.

What Are Lice?

Lice (singular louse) are wingless, flat, six-legged insects that attach to a host's hair shafts and feed on skin and blood. Lice are host-specific, meaning that each genus of animal is only infected by certain species of lice.

Symptoms of Lice in Dogs

Dogs can be infested with three species of lice: Linognathus setosusTrichodectes canis, and Heterodoxus spiniger . All species cause the same irritating symptoms in dogs.


  • Itching/scratching
  • Hair loss
  • Red, inflamed skin
  • Tiny, light-colored bugs among hairs
  • White flakes deep in the coat

The most common symptom of a lice infestation is extreme itchiness. Most dogs infected with lice suffer sudden fits of scratching, sometimes to the point of breaking the skin and causing bleeding. Untreated, lice can cause fur loss, trauma to the skin, and infection.

Upon close inspection, it is possible to see lice among the dog's hairs. Lice are light-colored and slow-moving. Fleas, by contrast, are dark and fast-moving, while ticks are dark and generally immobile. Because lice lay their eggs on the shafts of pet hairs, it's also possible to see their empty eggshells which look very much like dandruff. Any white flakes that are sticky and hard to remove from the hair are almost certainly unhatched lice eggs.

Causes of Lice

Lice are transmitted when a dog comes into contact with another dog that carries lice. If the dogs spend time together, then some of the lice will migrate from one to the other. Shared grooming tools can also transfer life. Transmission is most likely to occur in places where unfamiliar dogs congregate, such as:

  • Kennels
  • Pet stores
  • Pet adoption centers
  • Pet daycares
  • Pet shows
  • Dog parks
  • Rescue facilities

While poor sanitary conditions and crowding lend themselves to lice infestations, lice will take advantage of any social setting for dogs, such as agility events or even group walks.

Diagnosing Lice in Dogs

If you notice your dog scratching and suspect lice, visit your veterinarian to verify the source of itching. Lice are sometimes confused with fleas, mites, or even mange—all of which may require different treatment.

Your vet will examine your dog, carefully combing through the coat to look for signs of a specific parasite. If adult lice, eggs, or eggshells are obvious, then the diagnosis of lice is straightforward. Only if no apparent cause is found will your vet perform a skin scraping to rule out other itchy skin parasites.


Many chemical products kill and/or repel lice including fipronil and selamectin. While pharmaceuticals are very effective, a less toxic option is a lime-sulfur dip. While it may have a few side effects (such as the smell of sulfur and a short-term yellow tinge to your pet's fur), it works quite well. Discuss the frequency of the dips for lice with your veterinarian.

It can also be helpful to use a gentle shampoo and fine-toothed lice comb or flea comb to remove dead lice and sticky nits from your dog's fur. Sanitize combs after each use. Dispose of any bedding, brushes, or cloth toys that might be contaminated, and if possible, have furniture and rugs steam cleaned.

Prognosis for Dogs with Lice

If you have more than one dog, and one of your dogs contracts lice, it would be ideal to keep the infected animal away from the others during the course of treatment because the infestation is likely to spread. But, treatment can take weeks to achieve full eradication, so isolating dogs can be nearly impossible for this length of time. Ultimately, it may be best to treat all dogs because of how contagious lice are. Lice-infested dogs usually recover well if treatment is aggressive and persistent.

How to Prevent Lice

Year-round flea and tick prevention as recommended by your vet may be helpful in preventing lice infection. Discuss this with your veterinarian.

If you take your dog to shows, competition events, daycare, or obedience school, check the location ahead of time to be sure it's clean and well managed. If you take your dog to a groomer, inquire about how the grooming equipment is cleaned and sanitized in between clients. This will help avoid multiple parasitic bugs, including lice.

Are Dog Lice Contagious to Humans?

You cannot get lice from your family dog. Head lice that we see in school-aged children are a different species of lice. People do not get lice from dogs; nor do dogs get lice from people.

If you suspect your pet is sick, call your vet immediately. For health-related questions, always consult your veterinarian, as they have examined your pet, know the pet's health history, and can make the best recommendations for your pet.
Article Sources
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  1. Lice of Dogs. Merck Veterinary Manual.

  2. Lice. Animal Medical Hospital.