Demodectic Mange in Dogs

Demodicosis is a common inflammatory skin disease caused by microscopic mites and is often referred to as “mange”.  There are two types of mites that cause mange in dogs and they have different causes, concerns, and treatments.  The following information is regarding mange from Demodex mites.

What causes demodectic mange?

Demodex canis mites are normally found in small numbers in the skin of most healthy dogs.  They are transferred from the mother to the puppy within the first few days of life.  They live in the hair follicles and do not cause harm to normal dogs with healthy immune systems.  Demodectic mange occurs when there is an overgrowth of the normal population of mites.  This usually occurs in dogs with a weak or immature immune system, intestinal parasites, poor nutrition, dogs on immunosuppressive drugs, or due to transient stress.  It most commonly occurs in young puppies 3-6 months of age.  Adult onset lesions are usually associated with internal disease and immunosuppression.   

How is it diagnosed?

Dogs will usually present with hair loss with or without itchiness.  A microscopic sample of a deep skin scrape is necessary to confirm the diagnosis.  A skin biopsy can also be used to identify the mites. 

How is it treated?

Any predisposing factors or secondary skin infections should be immediately identified and treated.  Therapy depends on the size and extent of the lesions and if the dog has any underlying diseases.  Small local lesions can usually be treated with topical medications.  Larger lesions that expand over wider portions of the skin may need a combination of medicated shampoos and oral medications.  Many of the topical and oral medications are similar to heartworm preventatives, and dogs need to be heartworm tested before they are used.  There are also certain breed restrictions with these medications and their usage should be discussed with your veterinarian prior to initiating therapy.  Repeat deep skin scrapings are performed every 2-4 weeks during therapy, which should continue until two consecutive sets of skin scrapings are negative.  Generalized demodicosis can be a difficult condition to treat and can take several weeks.

What is the prognosis?

The prognosis is good for generalized young cases.  A small portion may relapse within a year and may require long-term treatment.  The prognosis for adult onset demodicosis is guarded. 

Can I get demodicosis from my dog?

Demodectic mange is not contagious to other animals or people. 



Côté, Etienne. Clinical Veterinary Advisor. St. Louis: Elsevier Mosby, 2011.  Print.

Hnilica, Keith.  Small Animal Dermatology A Color Atlas and Therapeutic Guide. St Louis:         Elsevier Mosby, 2011.  Print