Mange is term used for a range of skin diseases characterized by poor coat and skin condition. Mange is caused by a range of common exoparasites called mites, found mainly in companion dogs. Some species of these mites are normal residents of your pet whereas others are not. Their favorite place to reside is in the skin and hair follicles. If they are allowed to proliferate out of control, all mites can cause skin infections which can become severe if not treated. Because mites belong to the Acari (a subclass of arachnids) another term sometimes used for mite infestation is “acariasis”.
There are two major groups of mites that can infest your pet. These are Sarcoptes species, which burrow into skin, and Demodex species, which live in skin follicles.
Sarcoptic mange, also known as “canine scabies”, is caused by the Sarcoptes scabei mite This is a microscopic mite that is oval-shaped and light-colored. They are easily transferred between hosts. The canine sarcoptic mite can also infest cats, pigs, horses, sheep, and various other species. They cause itching due to their movement while burrowing through the skin. Hair loss and crusting usually occur, often seen first on the elbows and ears. Intense scratching and biting can cause skin damage, and secondary skin infections are common.
Demodectic mange is also called “demodicosis”, “demodex” or the “red mange”. It is indirectly caused by the Demodex canis mite. This is a species of mite that is naturally present on almost all dogs. They are transferred from the mother to her pups during suckling and close contact in the first few days of life. Normally, the immune system and scratching/biting behavior of your pet are able to cope with the natural population of mites and many dogs never suffer any consequences. However, if the animal has a compromised immune system and develops hypersensitivity to the mite, mange can begin.
Demodex canis is not the actual cause of mange, rather, it is due to a bacterium called Staphylococcus epidermidis. The demodex mite dilates the follicles and sweat-glands on your pet’s skin allowing the bacterium to enter the body. Demodex canis possibly also carries and introduces the bacterium.
Three types of demodectic mange are recognized.
- Localized mange occurs when the mites proliferate in only 1 or 2 (some say up to 4) small, confined areas, usually on the animal’s face. The resulting isolated, scaly, bald patches look like a polka-dot pattern. Localized demodicosis is common in puppies and approximately 90% of cases disappear without any treatment.
- Generalized demodectic mange affects larger areas of skin, sometimes the entire body. This becomes extremely itchy if there are secondary bacterial infections. The skin may also become foul-smelling. This form of mange can indicate underlying health problems or risk factors such as a compromised immune system, hereditary predisposition, or an endocrine problem. The course of treatment for the dog depends on the age at which the disease develops.
- Demodectic pododermatitis is a type of mange confined to the foot and is often accompanied by bacterial infections. It is one of the most resistant forms of mange. To make an effective diagnosis, deep biopsies are often required.
Transmission of sarcoptic mange mites usually requires direct host-to-host contact. Although mites can live off a host and in the environment for several weeks, they are infective for only 36 hours.
Although demodex mites are relatively easily transferred from one dog to another, it requires direct physical contact. In healthy animals, transmission of the mites simply adds to the dog’s natural population and there is no resulting skin disease. Even for severe cases, isolation of dogs is usually considered to be unnecessary. It is very rare for demodex mites to be transmitted to humans or cats.
The symptoms of mange vary, depending on the type type of mite causing the disease.
Sarcoptic mange can cause extremely intense itching. It can result in listlessness and frantic scratching, gradually increasing over several days. It also can result in hair loss (alopecia), reddened skin, sores and crusty scabs. In dogs, the most commonly affected areas are the ears, elbows, face and legs. In severe cases, it can spread rapidly over the entire body. Sarcoptic mange in humans causes a rash of red bumps, similar to mosquito bites.
Demodectic mange causes hair loss, bald spots, scabbing and dry sores. Secondary bacterial infections can make the dog extremely itchy and uncomfortable. Demodectic mange is not transmitted from dogs to humans. Demodex in pets can be detected by:
- Itching, bald patches, particularly around the mouth and eyes
- Itching, bald patches on the body and legs – spreading to cover the entire body
- Thick discharge from the ears, particularly in cats
- Leathery or wrinkly skin
A veterinarian will perform a physical exam of your pet and if necessary, take skin scrapings and examine these with a microscope to confirm the presence of mites. If the mites are buried deep in the skin, they can be difficult to identify. In such cases, the veterinarian may rely on your pet’s history and clinical signs to make a final diagnosis.
- Localized demodectic mange: Puppies and dogs less than 18 months old are especially prone.
- Generalized demodectic mange: Can be hereditary in dogs. Some breeds, such as the Dalmatian, American Bulldog and American Pit Bull Terrier appear to be more susceptible. Older dogs with and underlying illness are also more prone.
- Demodectic pododermatitis: The Old English Sheepdog and Shar Pei are particularly prone.
The medication given to your dog will depend on various factors such as the type of mange and the breed of dog. Medication may be given orally, by injection, by shampoo or dip, or applied topically (locally). It is important to realize that many skin treatments can be toxic to dogs. They should not be repeated frequently. Check with your vet before beginning any mange treatment program.
When treating sarcoptic mange, the first step is to isolate your dog to prevent the disease spreading to other pets (and humans). It is likely your vet will prescribe antiparasitic medications to eradicate the mites, as well as separate medications for easing itching, reducing inflammation and treating secondary skin infections. The results of such treatment are usually seen after 4 weeks
Demodectic mange is treated not only by medications but also by managing physiological stress to improve your pet’s immune system. To prevent secondary skin infections, some dogs may also require additional treatments, for example, medicated shampoos.
Younger dogs often fully recover from mange. In contrast, adult dogs often require long-term treatment and therapy to control the disease. It has been suggested that because demodectic mange is thought to be hereditary, dogs with the disease should not be bred.
Whichever treatment option is used, this should be accompanied by skin scrapes every 2 weeks. Usually, medication is discontinued after 2 consecutive scrapes are negative. A final scrape should be performed 4 weeks after treatment to check there has not been a recurrence.
- Sarcoptic mange: Thoroughly clean or replace the bedding and collar. Treat all animals in contact with your pet.
- Keep your pet away from animals you suspect might have the disease.
- Get periodic skin scrapes to ensure the mites have been eradicated.