Demodicosis is a skin disease caused by microscopic Demodex mites. Small numbers of these parasites are normally present in the skin. However, if an animal's immune system in not functioning well, the mites can take advantage of the situation, multiply and cause disease. Demodicosis is most commonly diagnosed in young dogs whose immune systems are not fully developed or in animals treated with drugs or suffering from diseases that cause immunosuppression. Some breeds of dogs are genetically predisposed to developing this condition. Demodicosis is also called demodectic or follicular mange.
Patchy hair loss is the hallmark of the most common, localized form of canine demodectic mange. Affected dogs are generally not very itchy and their skin looks relatively normal despite not being covered with fur. Generalized demodicosis is a more serious disease. These animals often have multiple, large areas of hair loss and obviously unhealthy looking skin that is very itchy. To diagnose demodectic mange, a veterinarian will lightly scrape the animal's skin in several places and look at the material underneath a microscope. In some cases, multiple scrapings are required before obtaining a sample that reveals the mites. If an underlying disorder is suspected, a full health work-up is in order.
Uncomplicated cases of localized demodicosis often resolve without any treatment. Antibiotics, oral medications that kill the mites and medicated dips and ointments can all be prescribed in more severe cases. If a case of demodicosis has been caused by drug therapy or an underlying disease, these problems must be successfully addressed if the dog is to return to normal.
Written by: Jennifer Coates, DVM
Last reviewed: October 2, 2008