Pediculosis in Dogs

Pediculosis is also known as lice. Lice are small insects that can live on your dog’s skin and hair coat. These parasites are flattened and do not have any wings. Once they find a host, they do not want to leave and will spend the extent of their life on him. There are several types of lice; those that suck blood and those that do not, preferring to chew on skin. The presence of lice on your dog can cause skin irritation, itchiness and in severe cases anemia. Without treatment, lice can spread to the entirety of your dog’s body.

The lice that are found on your dog are not the same as those that affect people. Young dogs, elderly dogs in unsanitary conditions and those who are malnourished are more likely to become infected; lice is not common in healthy pets that are kept clean.  Fortunately, lice are easily eradicated by topical insecticides.

Pediculosis, or lice, are parasites that can either suck the blood of your dog or chew on his skin.

Should your dog be infected with lice, you may notice the following:

• His hair coat is scruffy and dry
• He may lose some of his fur
• Continuous, sometimes severe itching
• Skin sores
• Anemia (can occur in heavy infestations with the lice that suck blood)

Lice are visible to the naked eye; adult lice can be 1 to 2.5mm long. They are often seen around the ears, neck and shoulders of your dog. 

Types 

Trichodectes canis and Heterodoxus spiniger are two common types of lice that are found on dogs; these are the lice that chew on your dog. They have large mouthparts and will grip onto your dog’s fur, chewing his dead skin cells. 

Linognathus setosus are the lice that suck on dogs. These parasites will grip the hair of their host with their claws and use their narrow mouthparts to suck blood through his skin. These are found all over the world and are usually more likely to be seen in long-haired dogs in places with colder temperatures.

Indirect or direct contact with other dogs that are infested with lice can lead to your dog contracting the parasites. When there are many dogs residing in close quarters the insects may spread easily; for example, in kennels and puppy mills. Both the lice that suck and the lice that chew can be transferred through direct contact or through contact with bedding, grooming materials or other items where lice are residing. The lice will lay eggs in the hair shafts of a dog. Cats and people will not be able to catch dog lice and dogs cannot catch lice from people.

If you see lice or eggs on your dog’s fur, or if you notice that your dog seems to be itchy and restless and/or is losing fur, it is recommended that you bring him to your veterinarian to be examined. You will want to report to your veterinarian any symptoms you have observed in your dog and when you first noticed them. 

Your veterinarian will conduct a physical examination of your dog and will use a microscope to take a closer look at a sample of his fur or skin scraping in order to confirm the presence and type of lice. The type of lice will be identified based on their mouthparts and in sucking lice, their further developed claws. Nits, or lice eggs, may also be observed. The majority of lice will be found under clumped or matted fur along your dog’s head, neck, shoulders, groin and tail. Your veterinarian will diagnose lice based on the symptoms your dog is experiencing and confirming the presence of the parasites.

Lice are the easiest parasites to eradicate in your dog; fortunately, treatment is straightforward. Your veterinarian may recommend bathing your dog with a pyrethrin shampoo. Upon your dog’s fur being dried completely a pyrethrin spray or powder may then be administered. In 10 to14 days, the treatment will be repeated as all of the lice and nits will not have been eliminated. Permethrins are able to effectively treat lice in dogs. Frontline or fipronil is another treatment option. While it is typically not required to treat your dog’s environment for lice, flea and tick foggers can be useful in severe infestations.

If your dog is infected with lice, he should be kept away from any other dogs he resides with until he has completed treatment. In order to avoid your dog being re-infected with lice, you will want to throw away or clean thoroughly items that he had had contact with (for example, bedding). You will also want to make sure that any places where your dog has spent time are cleaned sufficiently. As lice can only live for 3 to 7 days off of a host, any items that cannot be washed can be sealed in plastic bags for 4 to 6 weeks, which will allow time for the eggs to hatch and die. If your dog had a severe infestation with sucking lice, iron, vitamin and mineral supplements may be necessary. Monthly flea treatments will help to prevent future infestation with lice.