By Dial A Vet Veterinary Team
Hearing that your dog has mites can be alarming, but Demodex mites are a normal part of almost every dog's skin. Puppies pick them up from their mother in the first few days of life, and most dogs live with them for years without any sign. Problems start when the immune system cannot keep the mites in check and their numbers explode inside the hair follicles. That condition is demodectic mange, or demodicosis.
Key takeaways
- Demodex canis mites live in the hair follicles of most healthy dogs.
- Demodectic mange happens when mite numbers grow out of control, usually because the immune system is immature or weakened.
- It is not contagious to other dogs or people in normal circumstances.
- Localised mange in puppies often clears on its own. Generalised mange needs veterinary treatment.
- Demodectic mange appearing for the first time in an adult dog can be a sign of another illness.
Signs to look for
- Patchy hair loss, often starting around the eyes, mouth, face and front legs
- Thinning fur with scaling or redness
- Darkened skin in affected areas
- Red, bumpy or crusty skin
- Usually little itch early on, unless secondary infection develops
- In severe cases, swollen, painful skin, swollen paws, discharge, odour, and a dog who seems unwell
Types of demodectic mange
Localised
A few small patches of hair loss, usually on the face or front legs, most often in puppies between three and eighteen months of age. Many cases resolve as the puppy's immune system matures, though your vet will want to monitor and may recommend treatment.
Generalised
Larger areas or many patches of the body, or involvement of the paws (pododemodicosis). Generalised mange needs treatment and can lead to deep skin infections if left alone.
Juvenile onset versus adult onset
- Juvenile onset occurs in young dogs. There appears to be a hereditary predisposition, which is why affected dogs are usually not recommended for breeding.
- Adult onset appears in dogs over about four years old who have not had it before. It often signals that something is suppressing the immune system, such as Cushing's disease, hypothyroidism, diabetes, cancer, or long-term steroid or immunosuppressive medication. Your vet will usually recommend tests to look for an underlying cause.
Which dogs are at risk?
Any dog can be affected, but it is seen more often in puppies, short-coated breeds and some breeds with a known predisposition, including Staffordshire Bull Terriers, Shar Peis, Bulldogs, Boxers, Pugs and West Highland White Terriers. Stress, poor nutrition, heavy parasite burdens and illness can all make it more likely.
Is it contagious?
Not in practical terms. Puppies acquire Demodex from their mother during nursing, but healthy adult dogs do not catch demodectic mange from each other, and the dog mite does not infest people. This is different from sarcoptic mange, which is highly contagious. Our article on sarcoptic mange in puppies explains the difference.
When to see a vet
Book an appointment if you notice hair loss, scaling or redness on your dog's face, legs or body, especially in a young dog. Seek prompt care if:
- Patches are spreading or multiplying
- The skin is red, swollen, smelly or oozing
- The paws are swollen or painful
- Your dog seems lethargic, has a fever or stops eating
- An adult or senior dog develops hair loss for the first time
How vets diagnose it
Demodex is usually confirmed with a deep skin scraping, where the vet gently scrapes the skin until it bleeds slightly to reach the mites deep in the follicles, then looks under the microscope. Plucking hairs (a trichogram) or a sticky tape test can also find mites. In some cases, such as Shar Peis or thickened skin on the paws, a biopsy may be needed. For adult-onset cases, blood tests and other investigations look for an underlying condition.
How it is treated
Treatment has improved greatly in recent years. Many vets now use modern oral parasite products from the isoxazoline group, which can clear mites effectively and are much easier to give than older treatments. Other options include prescription topical treatments and medicated washes. Secondary bacterial infections are treated alongside, and your vet will address any underlying illness.
Some older treatments are dangerous for certain herding breeds, such as Collies and Australian Shepherds, that carry a gene mutation (MDR1) affecting drug sensitivity. This is one reason treatment should always be chosen by your vet.
Treatment usually continues until skin scrapings are negative on repeat checks, often for several months. Stopping too early is a common reason for relapse.
Supporting your dog at home
- Give all treatments exactly as prescribed and attend recheck appointments.
- Feed a complete, balanced diet.
- Keep your dog's stress levels low and their routine predictable.
- Keep up with flea, worm and tick prevention.
- Do not use essential oils, tea tree oil or home remedies on the skin.
FAQ
Can I catch Demodex from my dog?
No. Demodex mites are species specific. People have their own Demodex species.
Will demodectic mange come back?
Some dogs relapse, particularly if treatment stops early or an underlying condition is not controlled. Regular rechecks help.
Does demodectic mange itch?
Usually only mildly at first. Itching often increases if bacterial infection develops.
Should my dog be desexed?
Many vets recommend desexing dogs with juvenile generalised demodicosis, both to avoid passing on the predisposition and because hormonal changes during seasons can trigger flares in females.
Talk with a vet
If you have noticed patchy hair loss on your dog, a Dial A Vet veterinarian can look at photos, talk through the possible causes and help you plan the right tests with your local vet. Book a Dial A Vet consult.
References
- Mueller RS, Rosenkrantz W, Bensignor E, et al. Diagnosis and treatment of demodicosis in dogs and cats: clinical consensus guidelines of the World Association for Veterinary Dermatology. Veterinary Dermatology. 2020;31(1):4-25.
- Merck Veterinary Manual: Mange in dogs and cats
- Washington State University College of Veterinary Medicine: Multidrug sensitivity (MDR1) in dogs
Disclaimer: Educational only. This page does not replace an examination or advice from your own veterinarian. If you are worried about your pet right now, contact your local vet or nearest emergency animal hospital.
