Mange is a term used to cover any mite infestation on mammals. Mites are part of the arachnid family, thus they are related to spiders.
They are not insects. They are microscopically small and have evolved to live in many places. Dogs, and less often cats, can suffer from the following three types of mites and they can pass two of these on to us.
Sarcoptic mange is caused by the Sarcoptes scabiei mite. The movement of the adult and larval stages of the mites on the skin, as well as the burrowing of the females into the skin to lay eggs, causes intense itching.
The burrowed females and their eggs also stimulate a massive allergic response in the skin, exacerbating the itchiness. The skin will become red, scaly, thickened and oozy in affected areas.
Scabies mites prefer thinly haired skin, so signs usually first start on the flaps of the ears, the elbows and the tummy.
In severe cases, the lymph nodes will be enlarged and the dog may also suffer weight loss and be lethargic due to suffering from intense discomfort and itching. Very often the raw skin patches can become infected and this secondary bacterial infection will need to be treated as well.
If your vet suspects your dog is suffering from a mite infestation they will take some scrapes of the skin to look at under a microscope. The actual mites are only seen under the microscope in 50 percent of dogs infested with scabies.
Although these mites can be transmitted to humans, the condition they cause is usually self-limiting as we are not the preferred host. Signs of a scabies infection on humans are small red itchy bumps, usually on areas such as arms, which were in contact with our pets.
Treatment involves repeated dips or spot-on treatments for the infected dog and any in-contact dogs. Treatment can be prolonged and regular vet check-ups are necessary.
The second mite to infest a dog’s skin is the Demodex canis mite. These mites live in the hair follicles of the pet. In most dogs, Demodex mites are transmitted from the mom to the pup within a few days of birth, so low numbers of mites on a dog are considered normal. It is only when the population explodes and they start to cause clinical signs that the dog is considered to have demodectic mange or demodicosis.
Hair samples are taken either by plucking the hair or deep scrapings to examine under the microscope.
When young dogs become affected, called Juvenile Demodicosis, they are thought to have a genetic predisposition.
Adult dogs that suffer from Demodex infestations (adult-onset demodicosis) often have suppression of the immune system for some reason such as cancer, Cushing’s disease, hypothyroidism and immunosuppressive medications.
Infestations can be localised; isolated patchy areas of hair loss and reddened skin which is generally not that itchy, or it can be generalised.
A secondary bacterial infection can start up; the areas can bleed due to scratching, then scabbing over so in turn becoming itchier!
Treatment involves repeated dips or special oral medication with frequent check-ups at your vet.
It is important to treat the secondary bacterial infection too.
In adult dogs, any underlying disease suppressing the immune system will need to be treated as well. Young patients seem to do well with treatment and can often be completely cured.
In older adult dogs it can be much harder to cure and one will often just be able to manage the condition.
Lastly, we look at Walking dandruff or Cheyletiella mites.
Cheyletiella yasguri (dogs) and Cheyletiella blakei (cats) are less serious mite infestations of dogs and cats.
Cheyletiellosis causes flaky skin, dandruff, hair loss and raised red skin papules. The Cheyletiella mites, although tiny, can be seen with the naked eye.
Infested cats often over groom and this often causes significant hair loss. Your vet will need to take samples of hair to look at under the microscope to confirm the diagnosis.
It can potentially also be transmitted to humans. Mites on humans an live for quite a long time and cause a red itchy rash.
All dogs and cats that come into contact with an infected pet also need to be treated. There are various dips and spot-on treatments that can be used. It is also important to treat the environment with a spray or fogger to limit reinfestation. Provided treatment protocols are followed, the prognosis is good.