Itchy dogs: Mange and Mites

What is mange? 

Mange is used to describe a dog with mite infestation that has lead to skin disease. There are two (primary) types of mites that can cause mange in dogs, Sarcoptes and Demodex. Both live in different areas of the skin and there for have different symptoms and diagnostic methods. 

Symptoms

The sarcoptes mite lives on the superficial layers of the skin and causes crusting, scaling and intense itching. Many dogs then develop secondary bacterial infections that can cause pustules and even bleeding. Sarcoptes can affect any area of the body but is commonly seen as crusting on the ear margins. 

A case of severe Sarcoptes Infection I saw in China that had gone untreated for months, luckily she responded quickly to treatment.   

Demodex mites borrow into the gland and fur follicles of the skin, so the primary symptom is fur loss and they are rarely itchy. Demodecosis often presents as circular patches of hair loss that eventually become thickened and infected as secondary bacteria invades the skin. All dogs carry low numbers of demodex on their skin and in dogs with lowered immunity they multiply and cause disease. 

Diagnosis

   Sarcoptes mites can often be found by scraping the upper most layers of the skin and investigating the crusts under a microscope. Demodex mites on the other hand require deep skin scrapings, hair plucks or even biopsies to find the mites buried in the follicles. Skin scrapes can often be negative even when infection is present so veterinarians will also use the clinical signs classic to these diseases to make a diagnosis. 

Treatment

 Both mites can be treated using a antiparasitic medication called ivermectin. Generally Sarcoptes mange is easier to control and takes around four weeks to resolve. Demodex mites on the other hand can spontaneously resolve in puppies as their immune system develops.  But in older dogs or severe cases treatment has to continue until at least two negative skin scrapes are performed two weeks apart. This can take many months to resolve, and if the symptoms return it almost certainly means treatment was not continued long enough.  

Ivermectin can have side effects including seizures, and should never be used in Colliebreeds as they lack the enzyme to convert the drug. other antiparasitic medication can be used to treat both kinds of mange but many are even more toxic than ivermectin, or have very mixed results. ivermectin can be given orally or as an injection once a week for the duration of treatment.

Have you tried other treatments successfully in your dog? If so leave a comment to tell us what you used!

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