Scabies (Sarcoptic Mange) in Dogs

Mange is an umbrella term that refers to a number of different types of mite infestations in mammals, including humans. Sarcoptic mange, also known as scabies, is caused by the mite Sarcoptes scabiei.

The characteristic symptom that accompanies sarcoptic mange is extreme itchiness. Mange begins in locations where the hair is sparse, but left untreated, the mites spread to other parts of the body.

Severity depends on the extent of the infestation and how sensitive the dog is to the mites’ saliva.

Immunosuppression can cause a severe form of mange called “crusted scabies”. In these cases, there are large mite populations living in skin that has become excessively thickened and crusty.

Dogs who are in contact with other dogs with mange or wild animals such as foxes and wolves are at risk. The Sarcoptes scabiei mite can survive for 36 hours without a host, so dogs that are in contact with locations frequented by foxes and wolves (without having direct contact with wild animals) are also at risk.

Veterinary attention is required for dogs who have symptoms associated with mange. All dogs sharing a home with a dog who has a confirmed or suspected case of mange require treatment. Younger dogs, older dogs, and dogs who are immunocompromised are at greater risk from complications due to mange.

Bacterial and fungal infections of the skin are commonly associated with mange.

Infestations of Sarcoptes scabiei mites can travel to humans, although the mites do not thrive in conditions other than the ones to which they are adapted, so infestation on humans usually resolves itself quickly. Humans with infected dogs who have itchy areas on their body benefit from medical attention.

Scabies and mange are general terms for mite infestation, but the most common form in canines is sarcoptic mange, caused by the species Sarcoptes scabiei.

Sarcoptes scabiei mites live under the surface of the skin where the hair is sparse. Common areas of infestation include the edges of the ears, armpits, belly, elbows, and knees. The mites lay eggs under the skin. When the eggs hatch, the larvae dig new tunnels in the skin before molting to become nymphs and then adults. The life cycle takes 2 to 3 weeks.

The movement of the mites and their larvae on and under the skin causes itchiness. Itchiness is further intensified because the saliva of the mites triggers an immune response (allergies). Intense itching can lead to self-mutilation of the skin. Open skin wounds are susceptible to infection by bacteria or fungus.

Dogs that are scratching excessively require veterinary attention.

Diagnostic tools include:

• Physical examination
• Skin scrapes for microscopic analysis
• Response to a treatment trial

Confirmation of the presence of Sarcoptes scabiei is not always possible, even when an infestation is present. A presumptive diagnosis is made based on the symptoms and by treating for mange (treatment trial). If symptoms improve, mange is determined to be the cause. Otherwise, treatment for other causes of itchiness is pursued.

Treatment includes antiparasitic medications. These medications may be applied topically as a cream, spot-on product or dip, or orally in the form of pills, liquids, or chews. In some cases, these medications are labeled as treatment for fleas, but are used for the control of mange as well. Always consult a veterinarian before using topical medications on animals. Ensure treating vet staff are aware if there are other animals or children in the household. Some topical medications are toxic to cats and can be fatal even with indirect exposure.

Antibiotics or antifungals are required in cases with secondary infections in order to completely resolve symptoms. Some dogs benefit from the addition of anti-itch medications or itch relief shampoos while treatment is occurring.

Left untreated, mange will continue to progress indefinitely. The life cycle of the mite is 2 to 3 weeks, so infestation advances quickly.

Treatments take 4-6 weeks to eradicate mange. Reinfection is possible, so all dogs in the household must be treated to prevent continuous infection.

Washing bedding and other fabrics that the dog has had contact with or bagging them for 2 or 3 days to kill any live mites is also recommended to reduce environmental contamination.

Mange is highly contagious. Prevention of mange requires avoiding contact with infected animals. Elimination of contact with wild animals, locations frequented by foxes, wolves, or other carriers of the Sarcoptes scabiei mite, and infected dogs prevents infestation.

All dogs in the household require treatment if one becomes infected, due to the highly contagious nature of the mite. This treatment protocol also applies to multi-dog operations such as shelters, rescues, or breeders.

Mange is a very commonly diagnosed skin complaint in dogs.

• Antiparasitic medication
• Anti-itch medication
• Environmental controls