Demodex Mange
This week I saw a stray Chihuahua who had very bad skin. She was nearly bald and a skin scraping revealed she had thousands of tiny long thin mites in her skin. She had mange. There are two types of mange both caused by different types of mites. Sarcoptic mange is highly contagious and incredibly itchy. A different mite called demodex caused the type of mange the chihuahua had. Demodex mites are not contagious but a very common cause of skin disease across the NT.
The demodex mite is normally found in small numbers on the skin in healthy dogs. All dogs have a few but for most dogs the immune system keeps their numbers in check. For some dogs their immune system is not adequate to keep the mites under control, which allows a mite population explosion resulting in mange. Genetics play a big part in this and some breeds (particularly pit-bulls, sharpeis and staffys) are very prone to it. Ill health and a stressful environment (e.g. the tropics) can also reduce the immune system. Immature dogs with immune systems that have not fully developed get it commonly, which is why it’s also called puppy mange.
Most commonly it shows up as a patchy non-itchy hair loss but this can rapidly lead to bigger bald areas and if a secondary bacterial infection occurs then it can become itchy. The skin can then become thick, smelly and leathery – hence the nick name of “leather backs”
Many pups with patches of hair loss recover from the infection without treatment as their immune system matures. It can, however, become very nasty so treating it is recommended. Treatment is usually successful in pups but if in an adult dog you also need to look into other possible contributing causes. Rarely it can be a life long battle. Treatment consists of washes, antibiotics and either daily medication or weekly injections.
