What causes mange on a dog?

Mange is a skin condition caused by mites that affects dogs. There are two main types of mange in dogs – demodectic mange and sarcoptic mange. Mange causes severe itching, hair loss, and crusting of the skin. While mange is treatable, it can be painful and distressing for dogs. Understanding what causes mange will help dog owners better prevent, identify, and treat this condition.

What are the different types of mange in dogs?

The two main types of mange in dogs are:

  • Demodectic mange – Caused by demodex mites that live in hair follicles. These mites are normal residents on dog skin. Demodectic mange usually only causes problems in dogs with weakened immune systems. It is not contagious to other animals or people.
  • Sarcoptic mange – Caused by sarcoptes scabiei mites that live on the skin surface. These mites are contagious and can spread between dogs or to people. Sarcoptic mange is also known as canine scabies.

There are also other less common mites that can occasionally cause mange in dogs, such as cheyletiella and notoedres mites. However, demodex and sarcoptes are the main mite species veterinarians look for when diagnosing mange.

What causes demodectic mange in dogs?

Demodex mites are normal residents of dog hair follicles. They are usually kept in check by the dog’s immune system. However, in dogs with weakened immunity, the mites can overpopulate and cause demodectic mange. Causes of weakened immunity that allow demodex overgrowth include:

  • Puppies – Young dogs have immature immune systems that cannot control demodex mites.
  • Older dogs – Immune function declines in old age.
  • Illness – Diseases affecting the immune system like cancer or autoimmune disorders.
  • Medications – Drugs like steroids that suppress the immune system.
  • Stress – Chronic stress can impair immune function.
  • Poor nutrition – Deficiencies or poor quality food can weaken immunity.
  • Genetics – Some dog breeds seem genetically prone to demodex infections.

In puppies, normal immature immunity often allows a demodex overgrowth. This is called juvenile-onset demodectic mange. Puppies usually outgrow it as their immune system matures around 12-18 months old. Demodex mange in adult dogs usually indicates an underlying immune deficiency that should be investigated by a vet.

Which dog breeds are prone to demodectic mange?

Certain purebred dogs seem genetically prone to developing demodectic mange. Breeds reported to be overrepresented for demodex mange include:

  • Terriers – Boston Terriers, Bull Terriers, American Staffordshire Terriers
  • Bulldogs – English Bulldogs, French Bulldogs, American Bulldogs
  • Pugs
  • Chihuahuas
  • Great Danes
  • Dobermans
  • Shar Peis

However, demodex mites can overpopulate on any dog breed if immunity is weakened. Mixed breed dogs are also susceptible. Genetic predisposition likely involves inherited defects in immune regulation rather than a breed-specific mite variation.

What causes sarcoptic mange in dogs?

Sarcoptes mites live on the surface of the dog’s skin, rather than in hair follicles like demodex. Sarcoptes mites are contagious and can spread between dogs through close contact. They can also be transmitted between dogs and other animals, including people. Sources of Sarcoptes mite infection include:

  • Contact with an infected dog – This is the most common route of transmission between dogs.
  • Contact with an infected wild animal – Foxes, coyotes and wolves can carry Sarcoptes mites.
  • Contact with an infected human – Humans can temporarily carry dog Sarcoptes mites.
  • Highly contaminated environments – Mites can survive off-host in environments for several weeks.

Any dog can develop sarcoptic mange after exposure to Sarcoptes mites. Dogs with weaker immunity may develop more severe symptoms. There is no apparent breed predisposition for sarcoptic mange.

Can sarcoptic mange be transmitted between dogs and humans?

Yes, Sarcoptes mites can temporarily infect humans and cause itching and skin irritation. However, the mites cannot complete their life cycle on human skin and soon die off. Crusted scabies is a severe form of human Sarcoptes infection that can occur in elderly or disabled people who are unable to scratch and remove the mites.

To prevent transmission:

  • Isolate dogs with sarcoptic mange from other dogs and humans until treated.
  • Treat any infected humans and animals simultaneously.
  • Wash hands after handling affected animals.
  • Thoroughly clean environments that house infected dogs.

With good hygiene, human infection can be prevented. But sarcoptic mange is highly contagious between dogs in close contact.

What are the symptoms of mange in dogs?

The main symptoms of mange in dogs are:

  • Severe itching and scratching
  • Hair loss, thinning fur
  • Redness, irritation of the skin
  • Thick crusting of skin
  • Skin infections are common

Symptoms often start on the head, ears, elbows and hindlegs. As mange progresses, hair loss and crusting can spread across the entire body. Secondary skin infections are common because scratching damages the skin.

Demodectic mange symptoms tend to be localized patches of hair loss. Sarcoptic mange often has more generalized signs. But both types cause severe itching and can result in widespread lesions if not treated promptly.

Does mange make dogs smell bad?

Yes, dogs with mange often develop a strong, musty or foul body odor. This is caused by:

  • Buildup of skin crusts and oils – The thick crusting traps secretions on the skin.
  • Bacterial or yeast infections – These give a bad smell.
  • Skin inflammation – Causes abnormal skin secretions.
  • Greasiness – The hair coat appears greasy and matted.

While a bad smell is not directly caused by the mites, it is a common symptom of severe mange. The odor should improve with treatment as the skin heals.

How is mange diagnosed in dogs?

Veterinarians use several methods to diagnose mange in dogs:

  • Skin scrapings – Using a scalpel blade to collect skin debris, then looking at under the microscope to identify mites.
  • Skin biopsy – Taking a small skin sample to identify mites in the tissue.
  • Fungal culture – Testing for secondary fungal infections.
  • Blood tests – Complete blood count and blood chemistry to assess overall health.
  • Breed, age, history – Signal likelihood of mites based on risk factors.
  • Response to treatment – Improvement with antiparasitic drugs supports mange diagnosis.

Skin scrapings and biopsies allow visualization of mites to definitively diagnose mange. Vets also assess for secondary infections complicating mange cases.

Can my regular vet diagnose mange?

Yes, most regular veterinarians can diagnose and treat mange. They have access to the skin scrapes and biopsies needed to identify mites under the microscope. Some vets may send samples to diagnostic laboratories for analysis if uncertainty exists.

Severe or treatment-resistant cases may need referral to a veterinary dermatology specialist. Specialists have advanced training in diagnosing and managing difficult dermatology conditions.

How is mange treated in dogs?

Mange is treated using medications that kill mites and control secondary infections:

  • Antiparasitics – Medicated dips, spot-ons, pills kill mites. Often need to treat environment too.
  • Antibiotics – Treat secondary bacterial skin infections.
  • Antifungals – Treat secondary fungal or yeast skin infections.
  • Anti-itch drugs – Relieve itching while mites die off.
  • Shampoos – Antimicrobial and soothing shampoos help heal skin.
  • Immune boosters – Improve underlying immunity against mites.

Treatment is continued for several weeks until skin scrapings show mites have been eliminated. Environment must be thoroughly cleaned too. All in-contact dogs should be treated to prevent reinfection.

How long does it take to cure mange?

It usually takes 4-8 weeks to eliminate mites with appropriate treatment. However, visible skin lesions and hair regrowth can take 2-3 months to fully resolve. Treatment must continue until at least 2 negative skin scrapings are achieved.

Severe cases of mange can take up to 4 months to fully cure. Patience is needed as it takes time for damaged skin to heal after mites are killed. Relapses can occur if treatment is stopped too soon.

Can mange go away without treatment?

No, mange will not go away without treatment. Mites multiply and spread across the dog’s skin over time. Mange becomes more severe and difficult to cure if left untreated.

Even juvenile-onset demodex in puppies, which can resolve on its own as their immunity matures, still requires treatment. Allowing puppy mange to run its course risks permanent skin damage.

Early diagnosis and prompt treatment is key to effectively manage mange in dogs. Allowing it to progress leads to greater discomfort, treatment expense, and skin damage.

What is the best treatment for mange?

For most dogs, daily oral administration of prescription strength ivermectin or milbemycin for 4-8 weeks provides very effective treatment of mange. These oral heartworm prevention medications kill mites at doses high enough to treat active infections. Advantages of oral treatment include:

  • Convenient compared to frequent dips and spot-ons.
  • Achieves high drug concentrations systemically and at the skin.
  • Can also protect against heartworms and other internal parasites.
  • Oral ivermectin has activity against demodex, sarcoptes and most other mites.

Topical monthly spot-ons like moxidectin and selamectin are also effective for demodicosis. But sarcoptic mange often needs more frequent topical dosing.

How much does mange treatment cost?

On average, treating generalized mange costs $250 to $500. Costs may include:

  • Exam and skin scrapes – $50 to $100
  • Skin biopsy – $100 to $250
  • Antiparasitic drugs – $100 to $150
  • Antibiotics – $30 to $80
  • Follow up exams – $40 to $100

Severe cases requiring hospitalization, daily medicated dips, and specialist referral will cost $1500+ to treat. But most mange can be managed on an outpatient basis at a reasonable cost.

How can mange be prevented in dogs?

Strategies to prevent mange include:

  • Routine antiparasitic medications like heartworm preventives containing ivermectin, selamectin or milbemycin will prevent mites.
  • Avoid contact with wild animals like foxes that could carry mites.
  • Treat dogs in contact with affected animals.
  • Isolate dogs with sarcoptic mange to avoid spread.
  • Support immune health with good nutrition, vaccination, and preventive veterinary care.
  • Treat underlying illnesses contributing to immunodeficiency.
  • Reduce stress that may impair immune function.
  • Groom dogs regularly to prevent secondary skin issues.

Routine vet care and hygiene helps prevent mange in dogs at risk. Promptly treating any cases that arise limits contagion.

Can vaccinations prevent mange?

There are currently no approved vaccines to prevent mange. Vaccines work by stimulating antibody production against infections. But mange is caused by mites burrowing into the skin that are hard for antibodies to reach.

Vaccine research is ongoing, with some promising results in laboratory trials. However, mange prevention still relies on routine acaricide treatments and prompt case identification. Vaccines may provide additional protection when available in future.


Mange is an intensely itchy skin condition caused by mites infesting dogs. Understanding the causes like weakened immunity, genetics, and contagious spread helps owners prevent and identify mange. While frustrating to treat, modern medications can eliminate mange mites and allow dogs’ skin to heal. With veterinary care and diligent treatment, dogs can make a full recovery from mange. Through responsible ownership and routine prevention, dog lovers can keep their pets happy, healthy and mange-free.

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