Sarcoptic Mange (Scabies): Causes, Symptoms, & Treatments
Dr.Ajeet Singh ,Veterinary surgeon
Global Veterinary Clinic and Surgery Centre, Gorakhpur
Sarcoptic mange is a highly contagious skin disease found in dogs, caused by the Sarcoptes scabiei mite. These mites will burrow through the skin causing intense itching and irritation. The scratching that results from mange is what causes the majority of the animal’s hair to fall out. This is a treatable medical condition, but is highly contagious for other animals and humans. Pet owners are advised to keep the dog quarantined while it is being treated for mange.
This form of mange is caused by the mite Sarcoptes scabiei var canis. This highly contagious parasite is found on dogs worldwide. It is often called canine scabies. Although the mites that cause mange prefer dogs, humans and other animals that come in contact with an infected dog may also become infected.
The entire life cycle (17 to 21 days) of these mites is spent on the infested dog. Females burrow tunnels in the skin to lay eggs. Mange is easily spread between animals by contact. Indirect transmission, such as through infested bedding, is less common, but it can occur.
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Symptoms
These mites prefer hairless skin and tend to burrow into ear flaps, elbows, and the belly. Check those areas for red, scaly skin. In later stages, the ears may get a crusty edge.
Eventually, the mites will burrow anywhere on the dog’s skin, and the whole body will be affected.
The itching is intense and can make your dog really miserable. You may notice a rash and alopecia.
The signs and symptoms of sarcoptic mange in dogs are caused by the superficial burrowing of the scabies mite in your dog’s skin. These include:
- Severe itchiness
- Skin lesions
- Thickening of the skin
- Hair loss
- Lethargy
- Depression
- Secondary skin infections
- The defining symptom of sarcoptic mange in dogsis intense itchiness. As the condition progresses, the itchiness can lead to secondary signs like hair loss, dandruff, redness, small bumps, and scabs. These symptoms are usually found along the underside of the belly and on the elbows, ankles, and edges of the ears. In severe cases, these signs may spread to the rest of the body.
- In addition to these signs, some dogs may also be lethargic, have enlarged lymph nodes, and experience secondary skin infections caused by biting, scratching, and chewing. Extreme discomfort can even lead to a loss of appetite, which can lead to weight loss.
Types of mange
Also known as canine scabies, sarcoptic mange is a skin disease caused by oval-shaped, light-coloured microscopic mites that are contagious to canines and humans. In fact, this is how dogs pick it up – from other infected dogs (and why prevention involves keeping your pets away from infected dogs and treating all animals they are in regular contact with should it do the rounds.) Once transferred from the host to your pet, the female mites will penetrate the skin and lay eggs, which causes intense itching. Once the eggs hatch, larvae then tunnel under the skin, again bumping up the discomfort for your pooch.
They can be passed on to humans or cats or live on bedding or carpets for small amounts of time. Humans may notice a rash on the abdomen, arms or chest, while cats may develop an itchy face or neck area. That said, they do prefer the company of canines, and they usually self-resolve, unlike dogs, who will need to be treated.
Demodectic mange
Demodectic mange mites, on the other hand, live on all dogs, being transferred to a pup from normal cuddling with their mother in the first few days following birth. These mites generally cause no issues throughout the dog’s life. That said, when these mites overpopulate, dogs can develop three key types of demodectic mange:
- Localised mange, where the mites favour one or two small, confined areas, can result in scaly bald patches (often on the face). This is relatively common in puppies, and generally self resolves.
- Generalized demodectic mangeaffects a larger area – if not the whole body and may also lead to secondary bacterial infections, which can cause severe itching. This type of mange may be indicative of hereditary problems, immune system disorders, endocrine issues or other health conditions.
- The third, type, demodectic pododermatitisis accompanied by bacterial infections and is concentrated around the foot. Proper diagnosis usually requires a deep skin scrape
The incubation period varies from 10 days to 8 weeks, depending on how severely the dog is infested, part of the body affected, number of mites transmitted, and the individual dog’s health and hygiene.
Not all dogs have signs when they are infested with sarcoptic mange mites. Usually, though, the animal will have intense itching that comes on suddenly. The itching is probably caused by sensitivity to the mites’ droppings.
Initially, infested skin will erupt with small, solid bumps. Because the dog scratches or bites itself to relieve the itch, these bumps and the surrounding skin are often damaged, causing thick, crusted sores. Secondary yeast or bacterial infections can develop in the damaged skin.
Usually, the sores appear first on the abdomen, chest, ears, elbows, and legs. If the mange is not diagnosed and treated, the sores can spread over the entire body. Dogs with longterm, recurring mange develop oily dandruff (seborrhea), severe thickening of the skin with wrinkling and crust build-up, and oozing, weeping sores. Dogs affected this severely can become emaciated and may even die.
“Scabies incognito” is a term used to describe hard-to-diagnose mange. If a dog is regularly bathed and has a well-groomed coat, the mites might be hard to find, even if the dog shows signs of infestation such as itching. The other typical signs of mange—crusts and scales on the skin—are removed by regular bathing.
If mange is suspected, your veterinarian will do a physical examination, including collecting skin scrapings and possibly a stool sample. Some clinics might also use a blood test to diagnose mange. If mites are not found, but the signs are highly suggestive of mange, trial treatment is warranted.
Mange is very highly contagious and can spread easily between animals of different species and even to humans. Thus, you should ask your veterinarian for advice on how to avoid contracting mange from your pet.
Treatment should include all dogs and other animals that have been in contact with one another. It may be necessary to clip the hair. The crusts and dirt should be removed by soaking with a medicated (antiseborrheic) shampoo, and an anti-mite dip applied. Lime-sulfur is highly effective and safe for use in young animals. Several dips may be required.
Alternatively, internal or topical medicines are also effective. Some internal mange medications are also used for heartworm prevention, so your veterinarian may want to test your dog for heartworms before treatment. Treatment for secondary infections may also be necessary.
What Causes Sarcoptic Mange in Dogs?
Dogs contract sarcoptic mange from infected dogs. Wild canids like coyotes and foxes can also carry the mites, increasing the chances of infection for dogs in areas with large populations of wild canids.
Common causes:
- Direct contact with an infected dog
- Direct contact with a wild canid
Not all infected dogs show signs of sarcoptic mange, which means it is not always possible to determine where your dog picked up the condition. Once sarcoptic mange is suspected, however, it is a good idea to keep your dog away from other dogs to reduce the risk of spreading the infection.
High-stress environments like kennels and shelters pose an increased risk for contracting diseases like scabies. Stress can lower a dog’s immune system, making them more susceptible to parasites like scabies. This, combined with the proximity of other dogs, provides a route of infection for the skin mite to infect its host.
Diagnosing Sarcoptic Mange in Dogs
Sarcoptic mange is diagnosed through a combination of clinical signs and diagnostic testing. Scabies is suspected any time a dog presents with extreme itchiness. Skin lesions, hair loss, and other symptoms may also prompt your veterinarian to collect a skin scraping to confirm the diagnosis.
Veterinarians look for mites, mite eggs, and mite fecal material on the skin scraping, which all confirms sarcoptic mange. However, evidence of mites is found only 10% to 50% of the time. When evidence of mite activity is not found but scabies is suspected, veterinarians often proceed with treatment and base their diagnosis upon a positive response to the treatment. Additional diagnostic testing may still be recommended to rule out any other possible conditions.
Differentiating sarcoptic mange from other types of mange, like demodectic mange, or other skin conditions, like flea allergy dermatitis, is essential for accurate treatment and management. Your veterinarian may recommend additional diagnostic tests to rule out these conditions.
Treating Your Dog for Sarcoptic Mange
Dogs with sarcoptic mange are treated with anti-parasite medications. Your veterinarian may recommend a topical therapy, like weekly lime sulfur dips (only rarely recommended), selamectin (Revolution), and fipronal (Frontline). Your veterinarian may also suggest a systemic treatment. Oral systemic treatments include selamectin (Revolution), imidacloprid-moxidectin (Advantage Multi ) and off-label use of ivermectin. It’s pretty uncommon for vets to prescribe oral selamectin or imidacloprid.However, some breeds, like collies, have sensitivities to ivermectin that must be taken into consideration.
Two of the newest treatments for scabies are Nexgard and Bravecto. Both of these oral medications are flea preventatives but have since been discovered to be very effective in treating mites.
Your dog may also require treatment for any secondary bacterial or yeast infections that have arisen as a result of a scabies infection. To prevent further self-inflicted damage from biting and chewing, your veterinarian may also suggest medicated baths or anti-itch medications. Occasionally, an Elizabethan collar, or e-collar, may be recommended. All other dogs in the household should be treated for sarcoptic mange as well to reduce the risk of recurrence.
Recovery and Management of Sarcoptic Mange in dogs
The prognosis for sarcoptic mange in dogs is good. Most dogs recover with treatment, although severe cases may take longer to resolve. Continuing treatment for the prescribed period of time is crucial. The lifecycle of the mite is 21 days. Failure to treat for the recommended time may result in reinfection.
Sarcoptic mange is contagious. The best way to prevent reinfection is to treat all other dogs in the household, along with alerting regular playmates about your dog’s condition so that they can take appropriate preventative steps. In severe cases, the environment may also need to be treated with sprays recommended by your veterinarian.
Secondary infections can pose potentially serious complications. While most infections resolve with treatment, antibiotic resistant strains of certain diseases, like staphylococcus, can be challenging to treat.
Preventing Sarcoptic Mange in dogs
It is not always possible to prevent sarcoptic mange in dogs. However, avoiding contact with infected dogs is the surest way to prevent an infection. Signs of infection may not always be obvious, but observing the health of your dog’s playmates and talking with their owners can give you essential information about potential health risks.
There are no known breed predispositions to sarcoptic mange, but age can play a role. Younger dogs in high-stress environments like kennels, shelters, pet stores, grooming salons, and puppy mills may be more susceptible to the condition, and dogs with compromised immune systems are also at a higher risk.
