Lice (Pediculosis) in Dogs

Key Takeaways

Lice infestation, also known as pediculosis, describes parasitic infestation of the skin and hair with different species of lice. 

• Infestation is more commonly seen in young, debilitated, and malnourished dogs

• Chewing lice feed on the skin surface while sucking lice burrow into the skin and suck blood

• Both types produce dandruff, hair loss, and itch, but severe sucking louse infestations may also lead to anemia

• Investigation of lice involves physical examination and demonstration of lice in hair samples, or on microscopy

• Treatment options include antiparasitic medication alongside environmental insecticides and treatment of in-contact dogs

• Prognosis with treatment is excellent; some dogs occasionally require treatment for anemia

A Closer Look: What are Lice in Dogs?

Lice infestation is a distressing condition in dogs which results in itchiness and self injury. Most cases of lice infestation are mild and respond well to treatment, but untreated infestations with sucking lice sometimes result in anemia. Cases of lice infestation require prompt investigation and treatment with a veterinarian-prescribed antiparasitic medication.

Risk Factors

Lice are most commonly found in young dogs and are often seen soon after going home with a new owner. Lice often affect the skin on or around the ears initially, and are big enough to be seen with the naked eye.

Itchiness varies depending on the severity of the infestation and type of louse. Sucking lice normally result in more severe itchiness due to the disruption to the skin barrier and immune response from the host.

Possible Causes

Lice easily transfer from one dog to another via direct contact. Indirect transmission is possible via contact with infested hair follicles but is a less common transmission pathway.

Most species of lice primarily affect only one host species, but some species of sucking lice are able to infest cats and cross-species transmission occurs on rare occasions.

Main Symptoms

Symptoms of lice infestation include:


• Self injury

• Restlessness

Hair loss

• Dandruff

In rare instances where the lice consume enough blood to cause anemia, pale gums and lethargy may be noticed.

Testing and Diagnosis

Diagnosis of lice infestation includes:

• Physical examination

• Microscopy - demonstration of lice in the skin or on the hair follicles

• Blood work where anemia is suspected

Steps to Recovery

Treatment involves:

Antiparasitic medication: prescription products used at correct doses and intervals

Environmental treatment

• Treat all in-contact dogs and cats

• Environmental insecticide to prevent reinfestation

• Grooming 

Lice infestation becomes persistent in dogs without appropriate treatment but resolves quickly with antiparasitic medication administered on schedule as prescribed. The prognosis with treatment is excellent.


Lice infestation is preventable with routine use of veterinary antiparasitic medication at licensed doses. Most veterinarian-recommended flea and tick control products are also effective for preventing lice. 

Management of outbreaks involves isolation and treatment of symptomatic cases in combination with treatment of in-contact dogs.

Are Lice Common in Dogs?

Lice are common in dogs that don’t receive regular, preventive antiparasitic medication. Infestation is more common in puppies and malnourished or neglected dogs.

Typical Treatment

• Antiparasitic medication

• Environmental insecticide

• Grooming long haired dogs

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