Demodicosis in Dogs
It’s a terrible word.
It’s a terrible word because of all of the connotations of “suffering” and “ugly” and “difficult to cure.”
To veterinarians, it’s all that and a terrible word because we hear it as a catch-all term.
Over the next few days we’re going to discuss the four kinds of mange that occur in dogs, along with the cause of each one and its effects on canine patients.
Today we’re talking about Demodicosis, the parasitic skin condition caused by Demodex canis, the mite (insect) that causes “red mange” in dogs.
Demodicosis mites come from a mother dog and are transmitted to her pups only during the first seven days of life. Most commonly the mites move onto the face and front feet when the pups are nursing and treading with their front feet on the mother’s mammary (milk) glands. After seven days of life one dog cannot give another dog Demodicosis.
Many decades ago someone tried. A dog heavily infested with Demodicosis mites was literally lashed to another dog that had been born by Caesarean section and raised on a bottle so as to prevent Demodicosis mites from ever entering its body. Such pups are called SPF, or specific-pathogen-free. These two dogs were kept in constant contact for an entire month, and no Demodicosis mites ever entered the Demodicosis-free dog.
Demodicosis cases are broadly divided into two categories: localized and generalized. A localized case is limited to one or two lesions very close together. A generalized case, then, is one that has more than one lesion and the lesions are widely separated.
Lesions in Demodicosis typically are round to oval patches of hair loss, often with reddened skin (thus the common name) and a bumpy appearance where each hair follicle is located. Hair follicles are involved because most of the mites live around hair follicles, clogging the follicle as they live. A clogged hair follicle soon loses its hair shaft, resulting in bald patches.
When a Demodicosis patient is itchy the most common cause is the presence of secondary bacterial infection. When bacteria, even the normal bacteria that reside on a dog’s skin, invade beyond the surface of the skin, into the inner layers, itchiness results. Dogs with Demodicosis commonly have infection and infected skin can actually be a worse condition than the mites themselves.
Treatment is aimed at killing the mites. It is imperative that the pet owner understand that under no circumstances will all of the mites be killed by any treatment! Virtually 100% of dogs worldwide carry this mite, and eliminating all of the mites is physically and medically impossible. Our goal is simply to reduce the number of mites to a level the dog’s skin can tolerate until the immune system is again strong enough to keep the mites controlled on its own.
Outbreaks usually occur during periods of stress or maturation. Moving to a new home, illnesses, changing foods, surgery, puberty, these are all things that may cause the immune system to “dip” temporarily and result in a flourish of mites and the inevitable hair loss.
Methods of treatment vary widely, and your veterinarian must be consulted for proper treatment. Avoid home remedies which may not only make your pet’s skin worse but can even be fatal in some cases.
To read about Otodectic Mange (ear mites), click here.
To read about Sarcoptic mange, click here.
To read about Cheyletiella (Walking Dandruff), click here.
See you tomorrow, Dr. Randolph.