Effects of mites, mange

Most Trinis diagnose “mange” in any dog who starts to lose hair and develops patchy, flaky, itchy skin; and they either run down to their local pet shop for free (and often wrong advice) or throw old engine oil on the poor animal. Mange is a skin disease caused by one of several different species of parasitic mites. The mites that most commonly affect dogs are: Sarcoptes scabiei, which causes sarcoptic mange (canine scabies); Cheyletiella yasguri, which causes cheyletiellosis (walking dandruff); and Demodex canis, which causes demodicosis (demodex). Extensive superficial skin scrapings performed by a veterinarian must be done to diagnose any form of mange. Sarcoptes mites cause a non-seasonal, highly contagious and intensely itchy skin condition in dogs of all breeds, with no age or gender predisposition. People can be infected as well. These mites burrow through several layers of skin and not only mechanically irritate affected animals, but produce irritating allergic substances that exacerbate the hypersensitivity (allergic) reaction. The mites prefer areas of the skin where there is minimal hair, so the itching and scratching are often most intense on the ears, elbows, under the front legs and on the back of the hind legs, on the hocks, chest and across the groin and belly area. 

 

Untreated sarcoptic mange can lead to severe skin infections due to the scratching and accompanying allergic reaction to the mites. Red, inflamed bumps (pustules) can appear on the skin—which may darken, thicken and develop a leathery appearance. Self-inflicted wounds are especially prone to developing secondary bacterial infections. As the mites multiply, the condition worsens and can contribute to depression, aggression, lack of interest in play, inappetence, weight loss, significant hair loss and other physical and behavioural changes (such as obsessive compulsive disorder). Sarcoptic mange is best treated by medicated dips, shampoos and other prescription topical therapies prescribed by a veterinarian. Oral medication is available as well. Some breeds, especially Collies and Shelties, are intolerant to ivermectin—one of the medications often used to treat mange. These breeds need special attention to their treatment protocols. The environment and all animals in contact with an infected dog should also be treated. Cheyletiellosis is also highly contagious and causes marked skin scaling, which is normally most apparent on the dog’s back but can appear anywhere. It may or may not be accompanied by itching but, unlike the Sarcoptes mites, these mites do not cause deep and excessive underlying skin irritation. These large mites can easily be seen with a simple hand-held magnifying glass. People are subject to infection as well. This type of mange can be treated with shampoos and topical skin treatments prescribed by your veterinarian.

 

Common sources of infestation of Sarcoptes and Cheyletiellosis mites are boarding kennels, animal shelters, veterinary clinics, dog parks, grooming facilities and other high-density dog-friendly areas. The best way to prevent sarcoptic mange and cheyletiellosis is to avoid direct contact with affected animals. Demodex mites are normal residents (in small numbers) of the hair follicles and sebaceous glands of healthy dogs where they live and breed. However, in puppies and older dogs with compromised immune systems, these mites can proliferate. The most obvious clinical sign is patchy hair loss, which can be localised (occurring predominantly on the face, especially around the eyes and mouth) or generalised. Affected areas of skin often become oily, moderately scaly, crusty and thickened. Secondary bacterial skin infections are quite common as the mites multiply in hair follicles. Demodectic mange is not contagious to people or other animals and normally does not cause pruritus (itching). A genetic component has been suggested therefore any animal which is diagnosed with demodex should never be bred, but should be neutered. The mites are transmitted to puppies during nursing within the first 72 hours after birth. Demodectic mange can be treated through immune support, oral medication and dips. If your dog suddenly shows signs of intense itching and hair-loss, schedule an appointment with your registered veterinarian. Timely treatment will stop the spread of these parasites and your dog will be relieved of the pain and suffering caused.