New mites are being diagnosed in cats and new research is shedding light on the fascinating world of mites. Mites are much more common than you think.
A contagious skin parasite of cats, the Cheyletiella blakei mite is often referred to as “walking dandruff.” It usually causes pruritus (itching) and scaling of the skin, but sometimes the skin is normal. Skin lesions may also occur in people. Cheyletiellosis is more common in young cats, but any age can be affected. Heavy scales in the fur along the topline, or symmetric bilateral alopecia (hair loss) can develop. Your veterinarian will need to rule out flea allergy dermatitis, food allergy, and other skin diseases.
Diagnosis can be made by observation of the mite since Cheyletiella mites are large in size and visible without a microscope. Sometimes if needed, microscopic examination of skin debris can allow visualization of the mites. Every animal in the household should be treated. The parasite infestation may recur if the source of the mite remains untreated.
Demodicosis (Demodex cati, a Mange Mite)
The Demodex live in the hair follicles and sebaceous glands; problems develop when the number of mites exceeds that which is tolerated by the immune system. Usually the lesions are found around the eyes, face and head, and neck. Demodicosis causes an inflammatory reaction, often leading to secondary bacterial infections. Demodex mites can cause a patchy scaly reaction on the skin surface, and what we term ceruminous otitis externa, a greasy ear discharge. Immunosuppression, metabolic disease, and/or genetics may predispose certain cats to demodicosis. A newer mite, Demodex gatoi has been isolated in cats, and lives on the surface rather than down in the skin.
Your veterinarian will need to rule out dermatophytosis (ringworm), allergic dermatitis, and other dermatologic diseases. Diagnosis is usually made by microscopic identification of the mite in a skin scraping. A skin biopsy may be necessary in chronic cases where the mite cannot be identified via skin scrapings.
Often this type of mange is self limiting in cats and unless the cat has a chronic virus infection that causes immune system suppression such as Feline Leukemia Virus (FeLV) or Feline Immunodeficiency Virus (FIV), serious spread of the mite does not commonly occur. Other illnesses associated with generalized demodex lesions include diabetic cats, cats being treated with high dose cortisone-type drugs, and cats with cancer. Treatment in cats will be followed by repeat skin scrapings to make sure that the parasite has been cleared.
Ear mites (Otodectes cynotis)
These mites cause pruritus (itchiness) of the ears, head and neck. Less commonly, lesions extend back to the rump and tail area. Your veterinarian can diagnose ear mites by smearing ear debris on a microscope slide with mineral oil, and then identify the mite under a microscope. Ear mites are contagious and it is important to treat all animals in the household. The environment should also be thoroughly cleaned. Your veterinarian will prescribe appropriate medications to treat ear mites. Rarely, ear mites will bite humans as well but we are fortunately not the preferred host. If the infection is long-standing, considerable damage to the base of the ear may occur as the cat scratches away at the itchy ears. At this point, the cat may become quite painful to handle in this area. A typical ear mite discharge is black, dry and crumbly and sits in the ear canal. It is often described as “coffee ground” in appearance.
Treatment options include injections, topical anti-parasite medicine, and ear drops depending on the age of the cat and the severity of infestation. Follow up swabs of the ear canal will be recommended, usually about one month following therapy to make sure the infestation is cleared.
Notoedres cati (a Mange Mite)
This mite causes skin problems often referred to as “feline scabies” or the feline face mange mite. Very intense itchiness, and red, scaly skin with some hair loss is typical. As with demodex mite infestation, this is a rare cause of skin problems in cats, so your veterinarian may recommend testing for other conditions that could make your cat more susceptible to this parasite such as diabetes, cancer, FeLV, and FIV.
Feline Fur Mite
The uncommon mite Lynxacarus radovskyi leads to dandruff, itchy skin and hair loss.