Canine Demodicosis

Canine Demodicosis

Not All Mites Are Created Equal Demodex Mites

Demodicosis is a condition that occurs when the normally self-limiting population of demodex mites on a dog goes rogue. They are microscopic parasitic mites that inhabit hair follicles, oil glands, and skin. Demodex mites are non-contagious, host-specific, and are a normal skin inhabitant of dogs. Demodex mites are NOT Sarcoptes mites (which cause very itchy and contagious sarcoptic mange). Dogs of any age can have demodicosis. Young dogs most often get a transient overgrowth of mites that is localized to a few spots on the face or legs (see below: localized demodicosis). With a healthy immune response, the majority of these cases will resolve without treatment. Occasionally demodicosis completely takes the skin of its host hostage (see below: generalized demodicosis); it spreads to encompass very large areas of skin resulting in massive hair loss and other complications. Having a dog with hair loss can cause quite an issue for homeowners to clean, as well as keep control of the interior air quality due to the extreme hair loss. A good start to tackle this particular issue may be to get someone like a carpet cleaning company in to give the carpets a deep clean. This could improve the air quality, and stop any nasties developing within the fibers of the carpet itself. Demodicosis occurs sporadically in young dogs but accounts for the majority of the adult cases of demodicosis. The demodex life cycle is completed on the dog host. Dogs are infected with mites from their mother while nursing during the first week of life and will have mites throughout their lifetime (in low numbers).

Localized Demodicosis

This form of demodicosis presents as small areas of patchy hair loss and flakey skin. It is suspected that while the immune system is still developing, small populations of mites are allowed to overpopulate. In young dogs this is called juvenile focal demodicosis (commonly diagnosed in short-coated or wire-haired dogs and purebred dogs). Focal areas of hair loss are usually on the face, around the eyes, or on the legs. Once the immune system has appropriately responded to the parasite, the patchy hair loss will resolve without treatment in the majority of cases. Infections that do not resolve within a few months or continue to spread require treatments. Adults dogs very rarely get this type of infection.

Generalized Demodicosis

Generalized demodicosis occurs in both young and adult dogs and requires a thorough workup by a veterinarian to narrow down potential underlying causes. This condition can result in very large patches of hair loss in multiple places, oily midline skin secretions, discoloration and thickening of the skin, and an overall ill-thrift appearance. It almost always indicates an underlying health issue no matter what the age of onset, so be alert if these symptoms occur. Underlying health concerns could include: cancer, allergies, genetic propensity, endocrine disease, or other conditions or medications causing immunosuppression.


Demodicosis can mimic other diseases. Your pet's current and previous health history are a very important part of diagnostics. Dogs with unbalanced nutrition, poor preventative care, or those living in chronic states of stress are at higher risk of developing demodicosis in addition to many other health conditions. This is why preventative care and regular checkups are important in all pets to catch any abnormal or unhealthy conditions as early as possible. Most pet owners often tend to look at dog powder supplement to make up for any deficiency in their canine's nutrition as well. Your local veterinarian can diagnose demodex with some in-house tests. Skin scrapings and hair plucking from affected areas are the most common test samples. These can be examined microscopically for signs of mites. In dogs with deep skin infections or severely itchy or inflamed skin other tests may be utilized. In adult dogs with demodicosis, other diagnostics are also utilized to determine if an underlying health condition is present.


Once diagnosed, treatment can last several months and is dependant upon the dog's response to treatment and other concurrent health conditions. Treatment involves using miticidal (mite-killing) chemicals. There are many available treatments are not safe to use without prior knowledge of risks and side effects of the chemical in your pet. Your veterinarian can help choose the correct miticidal drug and treatment regimen for your pet. Routine vet visits and skin testing will be needed to confirm successful treatment outcome.

After Thought

The avermectin family of drugs has been a standby in the treatment of demodex as well as other canine parasites. While a very useful drug, it can be deadly in the wrong breed of dog or at the wrong dosages or when used in heartworm positive dogs. Never use avermectins in herding breed dogs (like collies or shepherds) without discussing the risks in detail with your pet's veterinarian. There is a genetic test available to determine if your dog has the avermectin sensitive gene. Other equally effective chemicals are available for at-risk breeds and the new chewable type of flea and tick preventatives (isoxazolines) have also shown promise as miticides.

### Amanda Burow, D.V.M. (Dr. B), is a graduate of Iowa State University's College of Veterinary Medicine. Dr. Burow's patient list includes hunting dogs of all varieties, as well as several field trial dogs and full time sporting guide dogs. In addition to practicing general veterinary medicine, she has special interest in the areas of preventive care, emergency medicine, and dermatology. In her spare time, she enjoys being outdoors and on the lake, staying active, reading, and spending time with family and friends. Mud River is proud to share these tips from Dr. B with our customers. Keep in mind it is best to work with your local veterinarian to determine the needs for your animals.