Demodicosis in Dogs: Causes, Symptoms, and Treatment

What is demodicosis in dogs?

Demodicosis is a parasitic skin condition caused by an overgrowth of the Demodex canis mite—a mite that is part of a dog’s normal skin flora and is present in small numbers in every healthy dog. It only becomes a problem when the immune system can no longer keep it under control.

There are two forms: localized demodicosis (few lesions, usually self-limiting, common in puppies) and generalized demodicosis (multiple lesions, affecting the entire body, requiring treatment). An important difference from scabies mites: Demodex mites are not transmissible to humans.

Background + Scientific Context

Mueller et al. (2012, Veterinary Dermatology, PubMed 22151742) published a comprehensive review on the treatment of canine demodicosis: Traditional treatment with amitraz baths is effective but associated with many side effects and is cumbersome. Oral ivermectin and milbemycin have shown good efficacy in studies—though caution is advised in breeds with the MDR1 defect (Collies, Shelties, Border Collies). The cure rate for generalized demodicosis varies greatly depending on the severity of the condition and the animal’s immune status.

Gortel (2006, Veterinary Clinics of North America, PubMed 16843813) described the pathogenesis and diagnosis: Demodicosis in puppies (juvenile) has a significantly better prognosis than in adult dogs—puppies often recover spontaneously, whereas adult dogs usually have an underlying immunodeficiency (Cushing’s disease, hypothyroidism, chemotherapy, long-term corticosteroid use). Diagnosis is made by skin scraping with microscopic detection of mites.

Beugnet et al. (2016, *Parasite*, PubMed 27075625) investigated the efficacy of afoxolaner (NexGard) against *Demodex canis*: Isoxazoline preparations (afoxolaner, fluralaner, sarolaner, lotilaner) demonstrated excellent efficacy against Demodex when administered monthly—with significantly greater comfort for both dogs and owners compared to amitraz baths. Isoxazolines have fundamentally transformed Demodex treatment in Europe.

Vitomalia-Position

Demodicosis is not a sign of neglect or poor hygiene. Every dog has these mites—it is only a weakened immune system that allows them to multiply. If you have a dog with generalized demodicosis, you should also look for the underlying cause—demodicosis in adult dogs without a triggering factor is rare.

When does demodicosis become a concern in dogs?

• If you notice bald spots, redness, or scabs on the face, around the eyes, or on the paws—especially in puppies
• In cases of generalized skin lesions with secondary bacterial infections (pyoderma)
• In immunocompromised dogs: Cushing's syndrome, hypothyroidism, chemotherapy
• For dog breeds with an MDR1 defect: Exercise caution with ivermectin-based treatment
• For differential diagnosis with Sarcoptes (scabies): Sarcoptes is highly contagious, causes severe itching, and can be transmitted to humans

Practical application

Diagnostic and Treatment Pathway:

Step	Action
1	Skin scrapings: microscopic detection of mites
2	Localized (< 5 lesions): wait and see; local treatment if necessary
3	In general: systemic isoxazolines (NexGard, Bravecto, Simparica)
4	Concomitant pyoderma: Antibiotics following a swab test
5	Check for underlying conditions: complete blood count, cortisol, thyroid function
6	Take a scraping sample every 4–6 weeks until two consecutive negative results are obtained

Important notes: - Breeds with MDR1 defects: Ivermectin is contraindicated — Genetic testing is required before starting treatment - Isoxazolines are the treatment of choice for uncomplicated generalized demodicosis - Recovery is considered confirmed only after two negative skin scrapings taken four weeks apart

Common Mistakes & Myths

• "Demodicosis is contagious." Demodex canis is not transmitted to humans and is rarely transmitted between dogs (only through close physical contact, such as from a mother to her puppies). It is not necessary to isolate the affected dog.
• “It’s just a minor case of eczema; it’ll go away on its own.” Localized demodicosis in puppies often clears up on its own—but generalized demodicosis in adult dogs does not. Misdiagnosis wastes time and leads to painful pyoderma.
• “The dog is dirty, which is why it has mites.” Demodex is part of the normal flora. Hygiene plays no role in the cause of the condition.

Current State of Research (2026)

Isoxazolines (afoxolaner, fluralaner, sarolaner, lotilaner) have largely replaced amitraz and ivermectin as first-line therapy—offering greater convenience and comparable or superior efficacy. To date, there have been few reports of resistance developing to isoxazolines. Ongoing studies are investigating the optimal duration of treatment and relapse prevention in immunocompromised dogs.

Frequently Asked Questions

How can I tell if my dog has demodicosis?

Typical symptoms: patchy hair loss, redness, and dandruff—usually starting on the face (around the eyes and muzzle) or on the paws. May or may not be accompanied by itching. If the condition spreads: extensive hair loss, scabs, and secondary infections. Diagnosis can only be made through skin scraping and microscopy.

How is demodicosis treated in dogs?

Current standard of care: monthly isoxazoline treatments (NexGard, Bravecto, Simparica). If pyoderma is present, add antibiotics. Duration of treatment: continue until at least two negative follow-up skin scrapings are obtained 4 weeks apart. Treat any underlying immunodeficiency concurrently.

Is demodicosis in dogs curable?

Juvenile (puppy) demodicosis: often resolves spontaneously. Generalized demodicosis in adult dogs: can be permanently cured with isoxazolines in ~80–90% of cases—provided the underlying condition is also treated. Relapses are possible in cases of persistent immunosuppression.

Related terms

• Parasites in Dogs
• Cushing's Syndrome in Dogs
• Skin Fungus in Dogs
• Complete blood count in dogs
• Dog Grooming

Sources & Further Reading

1. Mueller, R. S., Bensignor, E., Ferrer, L., Holm, B., Lemarie, S., Paradis, M., & Shipstone, M. A. (2012). A review of the therapy of canine demodicosis. Veterinary Dermatology, 23(2), 86–96. https://pubmed.ncbi.nlm.nih.gov/22151742/

2. Gortel, K. (2006). Update on canine demodicosis. Veterinary Clinics of North America: Small Animal Practice, 36(1), 229–241. https://pubmed.ncbi.nlm.nih.gov/16843813/

3. Beugnet, F., Halos, L., Larsen, D., & de Vos, C. (2016). Efficacy of oral afoxolaner for the treatment of canine generalised demodicosis. Parasite, 23, 14. https://pubmed.ncbi.nlm.nih.gov/27075625/