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Cat Lice (Felicola subrostratus) Infestation FAQ — Key Information Every Pet Owner Should Know

Infection/ParasitesQ&AMeongsiljang Veterinary Advisory Board

Cat lice (a parasitic infestation) is a highly contagious parasitic disease that causes hair loss and itching. We’ve compiled the essential information every pet owner should know in a Q&A format.

What is a cat lice (Felicola subrostratus) infestation?

A cat scratching its ears while baring its teeth

Feline lice infestation is a skin condition caused by external parasites called lice that live on a cat’s skin and fur. The only species of louse that infests cats is Felicola subrostratus, which is highly host-specific and spreads through direct contact with infected cats. While some cats may show no obvious signs of infection, common symptoms include itching (pruritus), restlessness, dandruff (scales), hair loss, and irritability. Lice attach their eggs firmly to the hair shafts; these eggs are called nits. Severe itching can lead to scratching and skin injuries, so early detection and proper management are important. If you suspect your cat has lice, it’s best to consult a veterinarian.

What are the main causes of lice (Felicola subrostratus) infestation?

The primary cause of cat lice infestations is direct contact with already-infected cats. Cat lice (Felicola subrostratus) are highly host-specific, so they mainly spread when cats of the same species come into direct physical contact. Because these lice firmly attach their eggs (nits) to hair shafts to reproduce, infestations can spread if cats live together or share combs, bedding, or grooming tools. Although lice do not survive long in the environment, reinfestation can occur through eggs or lice clinging to combs or bedding. As a result, infestations are more commonly seen in multi-cat households or environments with inadequate hygiene. Caution is also needed when introducing a new cat without proper health screening, as this can also lead to transmission.

What are the main symptoms of lice (Felicola subrostratus) infestation?

The main signs of a lice infestation in cats include itching (pruritus), restlessness, dandruff (scales), hair loss, and irritability. Some cats may remain asymptomatic with no obvious signs. When itching becomes severe, scratching and licking can cause redness (erythema) and abrasions, and chronic cases may lead to noticeable hair loss. A close inspection of the fur may reveal louse eggs (nits) attached to the hair shafts or dandruff-like debris. If these symptoms persist, secondary bacterial infections can develop in the wounds caused by scratching, so it is important to seek veterinary care early.

A cat with hair loss and wounds on its neck and ears.

Symptoms Requiring Immediate Veterinary Visit

If your cat is scratching or licking intensely to the point of causing skin wounds, redness, and swelling, or if you notice patchy hair loss, excessive dandruff, and visible eggs (nits), along with restlessness and increased sensitivity, it’s best to seek veterinary care. In particular, if the scratched areas develop oozing or scabs, there may be a secondary bacterial infection. Since other cats living in the same household can also become infected, it’s important to check them as well and not delay treatment.

How is a lice (Felicola subrostratus) infestation diagnosed?

Veterinarians carefully examine a cat’s coat and skin to check for lice and their eggs. While these parasites are relatively large and sometimes visible to the naked eye, accurate diagnosis often requires plucking hairs for microscopic examination (trichoscopy) or collecting skin debris with transparent tape for analysis. However, because confirming external parasitic infections can be challenging, veterinarians typically use multiple diagnostic methods in combination. Additionally, comprehensive testing may be necessary to differentiate this condition from other skin diseases that cause similar symptoms such as itching, dandruff, and hair loss, including demodicosis and fungal skin infections. Owners can aid the diagnostic process by keeping a record of their pet’s symptoms and any history of contact with other animals.

A veterinarian examining a cat's ear with a magnifying glass

How is a lice (Felicola subrostratus) infestation treated?

Treating feline lice (Felicola subrostratus) involves eliminating the parasites and removing their eggs and debris. Start by bathing the cat and thoroughly combing out tangled fur, dander, and nits, then apply an insecticidal medication. Feline lice respond well to most insecticides, and topical isoxazoline-class drugs are a good choice for cats. When using selamectin, it is important to mechanically remove debris, nits, and dander from the coat. Most importantly, all cats living in the same household must be treated simultaneously, and completing the full course of prescribed treatment is essential to prevent recurrence.

A veterinarian applying medication to the back of a cat's neck

Home Care and Prevention Methods

If your cat has a lice infestation, home care is crucial. It’s best to treat all cats that have been living with the infected cat. Lice don’t survive long in the environment, but eggs or lice can remain on combs, grooming tools, and bedding, leading to reinfestation. Therefore, thoroughly clean and organize your home, bedding, and grooming tools. Use medications prescribed by your veterinarian at the correct dosage and for the recommended duration. Even after treatment is complete, regularly check your cat’s fur and skin condition. To prevent future infestations, have new cats undergo a skin and coat examination, and establish regular brushing and cleanliness habits.

Step-by-Step Comparison of Managing Lice (Felicola subrostratus) Infestation

Item	Symptoms	How to Respond	Precautions
Mild	Slight itching, minor dandruff, eggs (nits) attached to the fur	Remove lice and eggs by bathing and combing, and start using insecticidal medication	Also check cohabiting cats, and continue treatment to the end
Moderate	Persistent itching, hair loss, skin wounds from scratching	See a veterinarian and start drug treatment such as topical insecticides	Prevent secondary bacterial infection, and wash bedding and grooming tools
Severe	Severe scratching with discharge and scabs, widespread hair loss, irritable and anxious behavior	Visit the clinic immediately and treat secondary bacterial infection concurrently	Treat all cohabiting cats and thoroughly disinfect the environment

Because the treatment approach differs depending on the severity of infestation, an accurate diagnosis along with a management plan that includes all animals living together is essential.

Reviewed by a veterinarian

Dr. Tony — Punnawat Phongkittirak

Veterinarian

A veterinarian who majored in veterinary medicine at Khon Kaen University, Thailand, and completed the IVSA program at North Carolina State University in the United States. Drawing on clinical experience at animal hospitals, he works in the pet healthcare field and is dedicated to building a digital care environment that connects pet parents with veterinarians.

Frequently Asked Questions

Can cats transmit diseases to humans?

Cat fleas (Felicola subrostratus) are highly host-specific and do not infest humans, as people and cats are parasitized by different flea species. However, for hygiene purposes, it is advisable to wash your hands after handling an infected cat.

Why does this infection keep coming back?

This infection can recur if other cats living in the same household are not treated, or if reinfestation occurs from eggs (nits) or lice remaining on combs, bedding, or grooming tools. Additionally, because the eggs adhere firmly to the hair, a single treatment may not eliminate them all. It is essential to treat all cats in the household and maintain a clean environment.

Can this infection be completely cured at home just by brushing?

No, brushing alone is not enough to completely remove flea eggs (called "fleas" in Korean) attached to the fur. To effectively treat the issue, you should combine thorough brushing and bathing to remove debris with the use of veterinarian-recommended flea control products (such as topical isoxazoline-based treatments for cats).

How long does it take to treat this infection?

The treatment duration depends on the severity of the infestation and the number of cats living in the household. Because the eggs (nits) adhere to the fur, a single treatment is often insufficient, and repeated applications may be necessary depending on the medication used. Complete recovery requires treating all cohabiting cats and thoroughly cleaning the environment, so it is important to follow your veterinarian’s guidance and maintain consistent care throughout the entire process.

Can this infection still occur even when using preventive deworming medications?

Even with preventive and deworming treatments, infection can still occur if your cat is newly exposed to an infected cat or contaminated items. Therefore, it’s important to manage all cats living in the same household, keep combs, bedding, and grooming tools clean, and regularly check your cat’s coat and skin condition.

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References

[1] Feline Emergency and Critical Care Medicine, 2nd Ed. (2023). Chapter 8: Infectious Dermatoses in Cats.

[2] The Cat, Clinical Medicine and Management, 2nd Edition. (2021). Section on Parasitic Skin Diseases.

[3] BSAVA Manual of Canine and Feline Dermatology, 4th Ed. (2020). Lice Infestations in Felines.