Australian Shepherd Health & Genetics Institute

Australian Shepherd Health & Genetics Institute

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Demodectic Mange


What is demodectic mange?

Demodectic mange, also known as demodicosis or “demo,” is due to the proliferation of hair follicle (demodex) mites normally kept in check by the dog’s immune system.   The condition may be limited and temporary (localized) or extensive, chronic, and/or recurring (generalized).  Localized demodicosis almost always occurs in dogs under a year of age.  The more serious generalized demodicosis usually arises before two years of age but can also start later in life.

Is demodectic mange autoimmune? 

No.  Autoimmune diseases are characterized by the immune system attacking its own body.  However, in demodicosis the immune system fails to control mites that are normal residents of the canine skin, allowing them to proliferate to the point they cause hair loss and, in the worst cases, skin irritation.  Generalized demodicosis appears to occur more frequently in Aussies with a family history of autoimmune disease, so it is possible these diseases have some form of immune system dysfunction in common.

How do I know if my dog has demodectic mange?

In puppies one year and under you may note one or a few areas of hair loss if the disease is localized.  Generalized demodicosis will involve larger portions of the body.  In addition to hair loss, the skin will appear irritated and rough.  In severe cases it can spread over most of the body.  Your veterinarian will confirm the diagnosis by microscopic examination of a skin scraping.

What does it mean for my dog if it has demodectic mange?

Localized demo is brought on by a temporary compromise of the immune system, usually in a young dog like your puppy.  The reaction may be triggered by travel stress, other illness, fatigue, or malnutrition, any of which can impact immune function.   Localized demodicosis will go away on its own and does not require treatment.  Generalized demodicosis is a serious disease.  It is not curable, but can be treated by controlling mite populations and medication to control secondary infections.   This is a life-long condition.  Affected dogs will have repeated outbreaks that will require treatment.  Generalized demodicosis can be life-threatening if not treated.

How common is generalized demodectic mange in Aussies?

It is common.  3% of the dogs in the ASHGI 2009-10 health survey were reported to have demodicosis.

Is demodectic mange inherited?

Localized demodicosis is not inherited.  Generalized demodicosis is genetically predisposed, meaning the dog must have the necessary genes but not every dog with the genes gets the disease.

Is there a screening test for demodectic mange?

Not at this time.

What does demodectic mange mean for my breeding program?

Localized demodicosis is not a breeding concern.  Because generalized demodicosis in Aussies is often found in families that also have autoimmune disease, breeders should consider it related to those diseases and part of a single health and breeding issue.