What is Demodectic Mange?

Mange is a parasitic infestation of a dog's skin by mites. The common symptoms are hair loss, itching, and inflammation.

Demodectic mange is caused by a microscopic mite called Demodex canis.  There are three species of Demodex mites but Demodex canis is the most common. This type of mange affects only dogs.  Different species of Demodex can affect cats but infection in cats is rare.

All dogs raised normally by their mothers possess this mite in their skin as the mites are transferred through direct contact during the first few days of life.  In some cases, such as a compromised immune system, poor nutrition, and also from genetic factors, the mites proliferate and cause skin disease. (Thus all dogs have this mite as a resident of their skin and it is generally not a contagious disease).

Demodectic mange is not contagious to humans.

The mites reside inside the hair follicles.  They have a life cycle of 25 to 30 days.

The first sign of hair loss does not occur until around 4 months of age (some pups will develop signs after weaning off their mothers; the lack of antibodies in their diet alters the immune system).

There are two forms of demodex mange:

1.  Localized:  this most often appears in dogs less than one year of age.  Patches of hair loss and red scaly lesions are usually found on the face and front legs.  There is a chance that the mange can self correct once the dogs immune system develops.  However, if there is not significant improvement and the lesions remain, the mange may become more generalized.

2.  Generalized:  this is the second form of mange where the entire dog can be affected with patchy fur, skin infections, baldness and scaly skin.  The skin may often become crusty with pus and scabs due to secondary bacterial infections.

What do you do if you suspect mange?

A suspected case of mange should be seen by a veterinarian. The veterinarian will take skin scrapings from several areas and examine them under the microscope to determine the presence of abnormally high numbers of mites.  

Treatment

Demodectic mange is almost always curable or controllable with persistent care.

Localized Demodex can be treated with medicated shampoos that contain benzoyl peroxide. A high quality diet, supplemented with omega fatty acids helps to boost the immune system.

More aggressive treatment is often needed for generalized demodicosis. Up to half of dogs that develop the generalized form will recover on their own, but treatment is always recommended.

The common treatment is Ivermectin, a liquid anti- parasitic medication.  The dosage varies by weight of the animal so they may need to be re-evaluated and have the medication amount altered. It can take several months of treatment for a dog to recover. Usually a veterinarian will take skin scrapings throughout the treatment to monitor the progress of recovery.

Often dogs with demodectic mange develop secondary skin infections and require antibiotics as well.

Advantage multi has also been used to kill off the mites; it also acts as a de-wormer and anti parasitic.  This is an alternative for collies that can potentially have seizures from Ivermectin.

Collie breeds and Ivermectin

If your dog is a collie or a collie mix, it is best to avoid Ivermectin as some collies have a mutant gene code for P-glycoprotein.  This is a large protein complex that acts to pump out the medications out of the brain and back into the bloodstream where they can be metabolized.  For the collies that lack the complete gene, there is a problem for pumping out the medication so that the drugs build up in the brain to toxic levels.

There is now a test available to see if the dog lacks the complete gene or not. 

Prevention

Treatment of demodectic mange only in part relies on medications; some basic steps can be taken with regard to pet care to maximize the chance of success. 

Stress is definitely a factor in the severity of mange. 

What can you do to help recovery?

1.  Have your female spayed as soon as the mites are under control.  Pregnancy, hormone changes and being in heat are stressful on the dog’s body.  If the dog has a predisposition to demodex, it should not be passed on to a future litter.

2.  Feed the best possible diet to help boost the dog’s immune system and provide nutritional support.  Some experts recommend a raw food diet to avoid any preservatives and fillers; this should be done under the supervision of a veterinarian to ensure the dog receives all vitamins and minerals.

3.  Keep the dog parasite free.  Adding in fleas, ticks or worms just makes it harder on their systems and cause further itchiness.

4.  Continue with wellness check ups and follow up skin scrapings if necessary.

Always follow veterinarian advice when handling mange cases as dogs may be sensitive to medications.  Proper feeding, lower stress and medication have an amazing effect on mange cases.