Mites are very small arthropods, with more than 30,000 described species, and possibly another 450,000 still unidentified. Most mites are not parasites but free-living predators that occupy just about every type of habitat on earth. The small number that are parasites live on the skin of mammals and birds, and feed on blood, lymph, skin debris, and skin secretions. Ectoparasitic mites spend their entire life cycle living on their host.
An ectoparasitic mite infestation is called acariasis and can cause severe dermatitis known as mange. The most common ectoparasitic mites on pets are Otodectes (ear mites), Sarcoptes (scabies), and Demodex (demodectic mange).
Ear Mites
Ear mites can cause an allergic reaction resulting in intense itching (pruritis) of the ear. Ear mites can affect dogs and cats of all ages and are very common in puppies and kittens. They leave thick, reddish-brown or black crusts on the outer ear and sometimes cause crusting and scales on the neck, rump, and tail. Secondary infections often occur as a result of the pet scratching or biting itself, to relieve itching.
Ear mites are very contagious, so it is important to treat the pet and the pet's environment. The pet's ears should be thoroughly cleaned with mineral oil (or an ear cleaner recommended by the veterinarian). A prescribed topical or systemic medication may then be applied.
Sarcoptes Mites
Sarcoptes mites cause a variety of skin problems, with the main symptoms being hair loss and itching. All breeds and ages of dog can be affected. The areas often affected first are elbows, ears, armpits, chest and ventral abdomen, but if left untreated the mites will spread over the whole body. Dogs are intensely itchy, with hair loss and often secondary infection. Diagnosis is made either by demonstrating the mite on a skin scrape, a positive blood result or response to treatment. There are a number of treatment options available which can be prescribed by your veterinary surgeon.
Demodex Mites
Demodex mites live in the skin follicles of all dogs without generally causing any problems. In a small number of animals these mites multiply in number and cause a skin problem. It is common in young dogs and often presents as focal, variably itchy hair loss. In severe cases the skin lesions can affect the whole body. Complications arise due to secondary bacterial and yeast infections. Diagnosis is made by demonstration of large numbers of the mites on a skin scrape. Treatment is often long and recovery may take months.