Treating Dog Lice

Reviewed, Edited and Updated by Dr. Omer Ahmed, DVM
December 2nd, 2023

Table of Contents

Lice Details | Symptoms | Diagnosis | Treatment | Prevention | MythsQ&A

What You Need. to Know:

Lice are small flightless external parasites or wingless insects which infest and live on the hair of animals and humans. An infestation is usually called pediculosis. Lice in dogs can cause skin irritation, discomfort and in severe cases results in skin infections.

There are two types of lice,(i.e. biting or chewing lice and blood sucking lice. Both can infest dogs and cause discomfort, skin irritation and other related integumentary (related to skin) symptoms. These are host specific, i.e. cannot be transmitted to animals other than dogs, and are not harmful to people. Canine lice cause the coat to feel scruffy and dry, and cause symptoms such as hair loss and severe itching. In cases of severe infestation, blood sucking canine lice can cause anemia, especially in puppies.

You can see dog lice with the naked eye. Dog lice are small insects, but they are large enough to be visible. They typically measure between 1 to 2 millimeters in length.

Diagnosis is based on clinical examination, where lice can be isolated from the dog's hair, and lice eggs can be examined under microscope. Getting rid of dog lice is accomplished with sprays, dips and bathes. Spraying disinfectants and anti-lice preparations in the dog’s environment and hygienic measures prevents repeated lice infestations.

Types of Dog Lice

Lice are flightless insects, also termed ecto-parasites (external parasites), which infest domestic animals and humans. These are host specific parasites, which depend upon the skin debris to feed and by sucking blood from the skin. Based on feeding pattern, lice are thus divided in to two different types; biting or chewing lice and blood-sucking lice. The chewing or biting lice belong to Anoplura order, while blood sucking lice are part of the Mallophaga order. Trichodectes canis and Heterodoxus spiniger are two common chewing or biting species of lice, while Linognathus setosus is the only blood sucking specie of lice, which infests pet dogs and causes clinical symptoms. Trichodecetes canis can also serve as a intermediate host for tape-worms in dogs.

Life Cycle and Transmission of Lice

Lice are typically host specific. They cannot fly and usually cause no problems for accidental hosts, such as on cats or humans etc. These are transmitted by direct, physical contact only and only adult or advance larval stages of canine lice can be transmitted from one dog to another. These are wingless parasites, therefore they cannot fly and physical contact is necessary for their transmission. Common places/means of transmission are parks, walking trails, beddings and grooming instruments.

Lice Symptoms

Lice cause discomfort to the infested dog. The first signs include scratching, rubbing and biting of infested areas. The dog’s coat will appear dry, rough and dull. Nits or eggs are sometimes mistaken for dandruff, and appear like white specks of sand. Itching and severe irritation are other notable signs, which cause stress and discomfort. The hair shaft may appear matted in heavy infestation. Sucking lice also causes small wounds, which may get infected. Thus stress, discomfort and small wounds can trigger other underlying disorders, such as secondary microbial skin infections. Symptoms usually appear on the head and ears as well as the rear, shoulders and neck.

Close-up of Cat Lice and Nits on Cat Hair
Lice and Nits on Cat Hair
Source: Washington State University

Blood sucking dog lice may cause anemia if they infest a dog in greater numbers; puppies are particularly more prone to anemia, since they have a less developed immune system and the skin is relatively immature. Clinically, a dog with a lice infestation appears stressed, dull and with severely dry and scruffy coat. Canine lice otherwise do not cause much damage to the health of your dog.

Diagnosis

Diagnosis is purely based upon clinical examination and hygienic history. Adult lice can be isolated from the base of the dog hairs, while eggs are usually glued with the hairs, which is why the hair can feel greasy. In order to diagnose, the pattern is observed. For example parting the hairs often reveals lice, where chewing lice appears active and blood-sucking lice usually moves slowly. If the veterinarian needs to confirm the type of dog lice, adult lice and/or eggs may be examined under microscope.

Treatment

Dog lice treatment or management of an infestation is usually done with the help of sprays, dips, bathes and thorough cleaning of the skin. Therapeutic elimination is necessary for proper treatment and several anti-parasitic drugs can be used for purpose. Dislodging with fine toothed combs usually don't  help much, because it's a tedious process and also it doesn't kill lice that have hatched.

These therapeutic agents that treat lice, such as pyrethrins, permethrin , lindane, rotenone, methoxychlor, diazinon, malathion, or coumaphos are commercially available in different formulations such as sprays, lotions, dips, dust and shampoos, with various therapeutic levels. Application of anti-paraistic/anti-lice preparation requires repeated doses in 10 – 14 days, because all canine lice nits are usually not killed in single application. 

A veterinarian should prescribe anti-parasitic drugs, and owners should follow the instructions of the veterinarian and before application clearly read the instructions on the label. One over the counter option is BioSpot Pyrethrins Dip for Dogs.

In severe infestations, i.e., in case of secondary microbial infections veterinarian might prescribe antibiotics as well.

Clearing the environment and surroundings with the help of different anti-parasitic sprays and washing the bedding and belongings of pets is essential in preventing canine lice infestation and transmission. Similarly, the infested dog should be kept separate from others.

Products such as Frontline Plus will control dog lice as well as other parasites.

Prevention

To keep your dog safe from lice, it's essential to take preventive measures. Here are some tipst o help you prevent lice infestations in your dog:

  • Regular Grooming: Brush and bathe your dog regularly to help detect and prevent lice infestations. Use a flea comb to check for lice and their eggs, especially in areas where they are commonly found.
  • Pet Hygiene: Keep your dog's living environment clean by washing their bedding and cleaning their living spaces regularly. This can help prevent lice from infesting your dog.
  • Avoid Contact with Infested Animals: Be careful with your dog's interactions with other animals that may be infested with lice, as lice can spread through direct contact.

Environmental Control

Since lice can survive in the environment for a short period, it's crucial to control the environment to prevent lice infestations:

  • Cleaning and Disinfecting: Clean and disinfect your home and any areas your dog frequents. Use specific cleaning agents effective against lice to ensure a thorough clean.
  • Laundry: Wash your dog's bedding, collars, and any fabric they have been in contact with regularly. Use hot water and high heat drying cycles to kill any potential lice or eggs.

Recognizing and Managing Recurrence

It's important to monitor your dog for signs of lice infestations and know how to manage a potential recurrence:

  • Monitoring: Regularly check your dog for signs of lice, especially after an infestation has been treated. Look for symptoms such as itching, hair loss, or visible evidence of lice or their eggs.
  • Follow-up Treatments: Follow your veterinarian's advice for follow-up treatments to ensure all lice and eggs are eradicated.
  • Long-Term Strategies: Maintain a routine for preventive treatments and regular veterinary check-ups to keep your dog safe from lice infestations.

Myths and Misconceptions

It's important to be aware of common myths and misconceptions about dog lice:

  • Human Transmission: While it's rare, dog lice can be transferred to humans. However, they are typically not harmful to people.
  • Home Remedies: Be cautious about using home remedies or over-the-counter products that are not specifically designed for dogs, as they may not be effective or safe.

When to Consult a Veterinarian

Knowing when to seek professional help is crucial for your dog's well-being:

  • Severe Infestations: If you suspect a severe infestation or if your dog shows signs of anemia, seek immediate veterinary attention.
  • Treatment Failure: If the initial treatments are not effective or if your dog has an adverse reaction, consult your veterinarian.
  • Health Complications: Be aware of potential health complications from lice infestations, such as skin infections or anemia, and seek veterinary care if needed.

By following these guidelines, you can help protect your dog from lice infestations and ensure their well-being.

Resources

Merck Veterinary Manual (2023 edition) 

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