Mites are crab-like external parasites that live on and inside of the skin, pores, hair follicles and hair coats of dogs, cats and many other mammals. The adult mites that infest dogs are tiny and have transparent to semitransparent bodies. Both of these characteristics distinguish them from ticks, which are larger and darker in color. In fact, Mites are so small that they cannot be seen with the naked eye, and can only be seen and accurately identified under a microscope. They typically range in size somewhere in the few hundreds of micromillimeters. To get some idea of how tiny these parasites are, one micromillimeter equals one-thousandth of a millimeter, and a millimeter is equivalent to 0.039 of an inch.
Types of Mites that Affect Dogs
There are four main species of mites that infest dogs: Sarcoptes scabiei (burrowing mites), Demodex canis (demodex mites), Cheyletiella yasguri (surface mites) and Otodectes cynosis (ear mites). Other mites, including Pneumonyssoides caninium (nasal mites), can infect dogs, but they are not nearly as common. The general term for a mite infestation is mange. Certain types of mites, including Sarcoptes and Cheyletiella, are highly contagious between dogs, and sometimes between dogs and people, as a result of direct animal-to-animal contact. Fortunately, most of the mites that affect dogs are not the same as those that affect people, and vice versa.
How Mites Affect Dogs and Why We Worry About Them
Mites are annoying creatures. However, because they are so tiny, owners don't actually see them crawling around on their dogs. What owners do see are the effects of the parasites. Mites almost always cause some degree of skin irritation and inflammation. Mites that burrow into the skin to feed and lay their eggs, such as Sarcoptes scabiei and the ear mite, Otodectes cyanosis, usually cause intense itchiness (pruritis). This can become so severe that affected animals will scratch, lick, chew, bite and rub frantically at the infested areas, sometimes to the point of self-mutilation. Dogs with ear mites will focus their efforts on their face, head, neck and ears; their symptoms in particular will include violent head-shaking and rubbing their head along the ground, trees, furniture or whatever other objects they can find. A dog's attempts to relieve the extreme discomfort caused by mites often cause weeping sores that are predisposed to developing secondary bacterial, viral or other skin infections (pyoderma). These open wounds can be extremely painful and almost impossible to treat, especially if the mites are not eliminated. Dogs with mites can also suffer from lack of appetite (anorexia), weight loss and relentless restlessness.
Some mites, including Demodex canis, cause mild to severe hair loss (alopecia), patchy red areas, thickened, dry, crusty skin (hyperkeratosis), skin redness (erythema), skin scaling and/or production of oily, smelly substances from affected areas (seborrhea). Demodex canis mites are normally present in low numbers in the hair follicles of all dogs. Puppies pick them up from close contact with their mothers within the first few days after they are born. Dogs only develop symptoms from demodex mites when their immune systems are immature, weakened or otherwise compromised, and therefore can't keep the mite numbers under control. This happens most frequently in young puppies and in older dogs that have some other illness or disease.
Cheyletiella yasguri mites, commonly called "walking dandruff," usually don't cause dogs to suffer any real discomfort, because they don't burrow into the skin. Instead, they live on the surface of the skin and feed off of dead and dying skin flakes and other superficial material. Sometimes, they do cause surface irritation, especially along the top of the dog's back. However, Cheyletiella mites like to bite people, especially on their forearms after they pet or groom an infested dog. This causes irritation and a rash-like reaction that typically resolves on its own.
Mites are often found on clean, healthy, well-fed and well-maintained companion dogs. Still, because many of these parasites are highly contagious, dogs kept in crowded living conditions, such as boarding kennels, animal shelters and pet stores, have a greater chance of becoming infested. Dogs with compromised immune systems are much more likely to develop the generalized form of demodectic mange, which can be fatal.
Mites are more difficult to detect than other external canine parasites because, unlike fleas, flies, ticks and lice, they can't be seen without a microscope. However, the effects of mites are usually fairly obvious: frantic attempts to relieve itching, patchy areas of hair loss, skin redness and irritation, skin sores and infection and/or skin thickening, crusting and scaling. The dog's veterinarian can take skin scrapings or biopsy sample of obviously affected areas and look at the samples a microscope to detect mites. There are a number of other ways that a veterinarian can identify the particular type of mites involved in mite infestations.
Treatment protocols will differ depending upon which species of mite is affecting the dog. There are a number of topical treatments, including dips, shampoos, powders, creams and lotions, that are effective against mites. Oral and injectable medications are also available to treat mites. The dog's immediate living environment and bedding should be cleaned and disinfected, along with grooming equipment, collars, leashes and any other areas or items that may harbor mites. Other pets in the household probably should also be treated. As always, a veterinarian is the best person to advise owners about the appropriate ways to prevent and treat mites in domestic dogs.
Fortunately, there are a number of things that owners of companion dogs can do to manage their pet's health and well-being and, at the same time, help prevent or resolve infestation by mites. A high-quality diet, free access to fresh water and a safe, temperature-controlled, low-stress living environment can all help keep a dog's immune system healthy and strong. Because most mites are contagious, owners may not want to let their dogs come into close physical contact with unfamiliar dogs. Owners should inspect boarding facilities before their dogs stay there, to make sure that there are clean and sanitary.
A good grooming program can be extremely helpful on a number of levels. First, regular grooming will help keep a dog's skin and coat healthy and clean. It also will give the owner (or groomer) an opportunity to look at the dog's skin and coat for evidence of external parasites. Sometimes, walking dandruff mites actually can be seen without a microscope, if they are moving. Dry or thickened skin, oozing wounds, redness, scaling and hair loss can all be identified during grooming. If a number of these conditions are found, it is probably worth a trip to the veterinarian. Prevention is certainly the best medicine. However, early detection and treatment of mite infestation is the next best thing. This is very important to the dog's overall health, and can be equally important to the health and well-being of other pets living in the dog's household.