Veterinary Guide to Canine Pediculosis (Lice) 2025 🐶🩺

By Dr. Duncan Houston BVSc

🧬 What Is Pediculosis?

Pediculosis, or lice infestation, in dogs involves small, wingless insects living on the coat and skin. Two main types occur:

• Chewing/biting lice (Trichodectes canis, Heterodoxus spiniger): consume skin debris and cause irritation. Some species can transmit the tapeworm Dipylidium caninum.
• Sucking lice (Linognathus setosus): feed on blood, can lead to anemia in severe cases.

Lice are host-specific, meaning canine lice don’t infest humans or cats.

⚠️ Who Is at Risk?

• Puppies, senior dogs, or immunocompromised dogs.
• Neglected, stray, or overcrowded dogs.
• Long-haired breeds are more susceptible to heavy infestations.
• Dogs in kennels, show venues, or day-care settings.

👀 Clinical Signs

• Severe itchiness, scratching, rubbing, restlessness.
• Rough, dull or matted coat; dry skin; possible fur loss.
• Wing or military bleeding, anemia signs if sucking lice are heavy in young or small dogs.
• Nits (eggs) clinging to hair shafts; often mistaken for dandruff.
• Possible secondary bacterial infections from scratching.

🔍 Diagnosis

1. Visual exam—part coat and look for adult lice or nits (~2–4 mm, light brown/grey, slow-moving).
2. Use a fine-toothed flea comb to collect lice or eggs; contrast on white paper helps.
3. Skin scraping or acetate tape test to differentiate from mites or fleas.

🛠️ Treatment

Effective eradication combines direct parasite removal, topical or systemic insecticides, and environmental control.

• Topical Spot‑Ons & Dips

• Fipronil, imidacloprid, selamectin: proven lice killers, often in flea/tick preventatives.
• Permethrin, pyrethrins: effective shampoos, sprays—but use permethrin only for dogs, never cats.
• Isoxazolines (fluralaner, afoxolaner): single dose may suffice; veterinary Partner notes need only 1–2 doses.

• Shampoos, Dusts & Collars

• Insecticidal shampoos containing pyrethrins provide rapid relief.
• Dusts/sprays for bedding and surroundings are recommended by Merck.
• Collars (e.g., propoxur)—mostly obsolete; spot‑ons currently preferred.

• Re-treatment & Grooming

• Repeat treatment 7–10 days after the first to catch hatching eggs.
• Bathroomly groom with a flea comb to physically remove lice & nits.
• Clip heavily matted coats as needed.

• Addressing Anemia

• Severe sucking lice infestations—especially in puppies—may need iron/vitamin supplementation.
• Monitor hematocrit in serious cases.

🏡 Environmental Control & Prevention

• Wash bedding, blankets, collars, brushes with hot water; treat pet’s environment.
• Treat all in-contact dogs—even asymptomatic ones—to prevent reinfestation.
• Maintain regular flea/tick prevention year-round—most prevent lice too.
• Keep dog environments clean, well-groomed, and avoid overcrowding.

📈 Prognosis

• Excellent with proper treatment and environmental control.
• Chronic infestations in neglected dogs require multiple treatments and close follow-up.
• Anemia and secondary infections resolve with supportive care.

📱 Ask A Vet Telehealth Support

• 📸 Owners share grooming photos or video of lice/eggs for remote review and treatment advice.
• 🔔 Reminders for treatment schedule, grooming tasks, and environmental cleaning.
• 🩺 Virtual consults to assess coat condition, skin healing, and scratching behavior.

🎓 Case Spotlight: “Milo” the Maltese

Milo, a 10-week-old Maltese puppy, had intense scratching and flaky skin. Chewing lice were identified via combing. Treatment included spot-on selamectin, follow-up after 10 days, environmental cleaning, and comb-out twice weekly. Ask A Vet helped monitor improvements.🐾

🔚 Key Takeaways

1. Pediculosis in dogs includes both chewing and sucking lice, diagnosed visually with comb and examination.
2. Treat with proven topical/systemic options: fipronil, imidacloprid, selamectin, permethrins, or isoxazolines.
3. Repeat treatment after 7–10 days and groom combs to remove live lice/nits.
4. Environmental cleaning and treating all in-contact pets reduce reinfestation.
5. Prognosis is excellent with timely, comprehensive management.
6. Ask A Vet telehealth supports diagnosis, treatment scheduling, remote assessment, supply delivery, and progress tracking 🐾📲

Dr Duncan Houston BVSc, founder of Ask A Vet. Download the Ask A Vet app for expert telehealth help—from lice detection and treatment guidance to grooming instruction, supply coordination, and long-term monitoring for your dog’s skin wellness 🐶📲