Sarcoptes scabiei var. canis
Also known as: Canine Scabies, Scabies
In short
Sarcoptic mange, or canine scabies, is a highly contagious and intensely itchy skin disease caused by microscopic burrowing mites. It spreads rapidly among dogs and wildlife, causing severe scratching, hair loss, and skin crusts. Fortunately, with prompt veterinary diagnosis and targeted antiparasitic treatment, this painful condition can be completely cured.
TL;DR. Sarcoptic mange is a highly contagious, intensely itchy skin disease caused by microscopic burrowing mites that requires prompt veterinary diagnosis and targeted antiparasitic treatment to cure.
Intense, nonseasonal scratching is the primary hallmark of sarcoptic mange in dogs.
Sarcoptic mange, commonly known as canine scabies, is a highly contagious and nonseasonal skin disease that affects dogs of all ages, breeds, and sizes. The condition is caused by Sarcoptes scabiei var. canis, a microscopic, circular mite that lives its entire life cycle on the dog. These parasites burrow into the superficial layers of the skin—specifically the stratum corneum—where they feed, mate, and lay eggs.
This burrowing activity, combined with the dog's immune response to the mite's saliva, feces, and physical presence, triggers an intense, relentless allergic reaction. The resulting itch is often described as one of the most severe pruritic conditions a dog can experience. Unlike normal itching, the discomfort from sarcoptic mange is constant and does not fluctuate with the seasons.
As the disease progresses, the constant scratching, biting, and licking lead to severe self-trauma, secondary bacterial and yeast infections, and a significant decline in the dog's quality of life. Because the mites are highly contagious, they can easily spread to other pets in the household and can even temporarily transfer to humans, causing itchy, red welts. Understanding how this parasite behaves and recognizing the signs early is crucial for protecting your dog and your family.
The primary cause of sarcoptic mange is direct contact with an infected animal. In many cases, wild canids serve as the reservoir for the disease. As noted in a leading veterinary dermatology reference:
"Wildlife such as fox and coyotes are often the source of initial infection and possible repeated infections. In multiple-dog households, more than one dog is usually affected. Canine scabies is a nonseasonal intense pruritus that responds only variably to corticosteroids." — Small-Animal-Dermatology-A-Color-Atlas-and-Therapeutic-Guide, p. 144
Because the mites can survive off a host in the environment for several days to a few weeks (depending on temperature and humidity), indirect transmission is also possible. This can occur through contaminated bedding, grooming tools, kennels, or areas where wild foxes or coyotes have recently slept.
While any dog can contract sarcoptic mange, certain factors increase the risk of exposure:
The symptoms of sarcoptic mange are primarily driven by the dog's intense allergic reaction to the mites. The signs typically start on areas of the body with less hair, such as the ear margins, elbows, hocks, chest, and belly, before spreading across the entire body.
Thick, yellow-gray crusts along the ear margins are a classic clinical sign of canine scabies.
Diagnosing sarcoptic mange can be challenging because the clinical signs closely mimic other itchy skin conditions, such as flea allergy dermatitis, food allergies, or environmental allergies. Your vet will use a combination of physical examination findings, history, and specific diagnostic tests to reach a diagnosis.
One of the simplest and most reliable clinical tests your vet will perform is the pinnal-pedal reflex test. The vet will gently rub the edge of your dog's ear flap (the pinna) between their fingers. If the dog responds by rapidly scratching with their hind leg (the pedal motion), the test is considered positive. While not 100% diagnostic on its own, a positive pinnal-pedal reflex is highly suggestive of sarcoptic mange.
To confirm the presence of the mites, your vet will perform deep skin scrapings. Using a dull scalpel blade, the vet will gently scrape multiple affected areas of the skin—particularly the ear margins and elbows—until a small amount of capillary bleeding occurs. This is necessary because the mites burrow deep within the outer layer of the skin. The scraped material is then mixed with mineral oil and examined under a microscope.
However, finding the mites can be incredibly difficult. Because of the severe allergic reaction, a dog can scratch intensely even if only a few mites are present. It is estimated that skin scrapes are false-negative in up to 50% to 60% of active sarcoptic mange cases. Therefore, a negative skin scrape does not rule out the disease.
In chronic, atypical, or difficult-to-diagnose cases, your vet may recommend a skin biopsy (dermatohistopathology). A small piece of skin is surgically removed under local or general anesthesia and sent to a veterinary pathologist. The pathologist looks for characteristic inflammatory patterns and, occasionally, the physical presence of the mites or their eggs within the tissue layers.
Because of the difficulty in finding the mites on skin scrapes, vets will frequently recommend an empirical treatment trial if they highly suspect sarcoptic mange based on the dog's history and symptoms. If the dog's itching improves significantly after starting scabies treatment, the diagnosis is confirmed.
Treating sarcoptic mange requires eliminating the mites from the dog, treating all other in-contact animals, and addressing any secondary skin infections.
The primary line of treatment involves antiparasitic medications. Historically, lime-sulfur dips and organophosphate rinses were used, but these have largely been replaced by safer, highly effective systemic medications.
Macrocyclic lactones, specifically Ivermectin, are highly effective antiparasitic treatments. However, because of potential toxicities in certain breeds, vets must use precise dosing protocols. A leading veterinary drug handbook outlines a common titration protocol used to safely introduce the drug:
"Start at low dosage and increase:
Day 1: 100 micrograms/kg PO q24h,
Day 4: 200 micrograms/kg PO q24h,
Day 7: 300 micrograms/kg; continue to increase by 100 micro-grams/kg every 3rd day until reach target dose of 600 micrograms/kg PO daily and continue treatment 1–2 months after 2 negative skin scrapes. Treatment usually requires 10–33 weeks." — Plumb's Veterinary Drug Handbook, p. 1985
Note: This specific high-dose titration protocol is often utilized for demodicosis but demonstrates the careful approach required when administering macrocyclic lactones over extended periods.
In modern veterinary practice, newer classes of antiparasitics, such as isoxazolines (oral chewables typically used for monthly flea and tick prevention), have become the standard of care due to their high safety margin and ease of use. Your vet will select the safest and most effective medication for your specific dog.
Because the dog's skin barrier is severely compromised by constant scratching, secondary bacterial and yeast infections are very common. Your vet may prescribe:
While our structured clinical database does not list a formal prognosis statistic for this species, standard veterinary clinical experience indicates that the prognosis for sarcoptic mange is excellent with appropriate, complete treatment.
Once the correct antiparasitic therapy is initiated, the itching typically begins to subside within one to two weeks. Complete resolution of skin lesions and hair regrowth can take several weeks to a few months, depending on the severity of the initial infection. It is vital to complete the entire course of treatment prescribed by your vet, even if your dog appears completely cured, to ensure all mites and newly hatched eggs are fully eradicated.
Preventing sarcoptic mange involves minimizing exposure to the mites and maintaining routine parasite control:
Sarcoptic mange is not a sudden, life-threatening emergency, but it causes extreme distress and discomfort. You should schedule an appointment with your vet if you notice your dog scratching relentlessly, especially if they are developing hair loss, red skin, or crusts on their ears and elbows.
You should seek immediate veterinary care if:
Special consideration must be given to herding breeds, particularly the Collie. Collies and closely related breeds (such as Shetland Sheepdogs, Australian Shepherds, and Old English Sheepdogs) frequently carry a genetic mutation in the ABCB1 gene (formerly known as the MDR1 gene).
This mutation affects the production of P-glycoprotein, a protein responsible for pumping toxins and drugs out of the brain. Dogs with this mutation cannot safely process certain drugs, including high doses of macrocyclic lactones like ivermectin. If given these medications, the drugs cross the blood-brain barrier and accumulate in the central nervous system, leading to severe, life-threatening neurological toxicity.
If you own a Collie or a related breed, your vet will likely recommend a genetic test to check for the MDR1 mutation before prescribing any macrocyclic lactone. Alternatively, they will use safer, alternative classes of antiparasitics (such as isoxazolines) that do not carry the same risk of toxicity in these sensitive breeds.
Treatment must be prescribed by a licensed veterinarian based on your pet. Specific drug doses are intentionally not shown here.
Sarcoptic mange, or canine scabies, is a highly contagious and intensely itchy skin disease caused by microscopic burrowing mites. It spreads rapidly among dogs and wildlife, causing severe scratching, hair loss, and skin crusts. Fortunately, with prompt veterinary diagnosis and targeted antiparasitic treatment, this painful condition can be completely cured.
intense pruritus、Alopecia、Erythema、Excoriations、Papules、Peripheral lymphadenomegaly、crusts、Secondary weight loss
Deep skin scrape microscopy、Dermatohistopathology、Pinnal-pedal reflex (ear scratch test)
Treatment must be prescribed by a licensed veterinarian based on your pet. Specific drug doses are intentionally not shown here.
This article is for general education and is not a substitute for professional veterinary advice. If your pet is unwell, please consult a veterinarian.
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