Demodex, also called demodicosis and demodectic mange, is a type of skin disease caused by the parasite Demodex canis. The cigar-shaped parasites live among the hair follicles of dogs, spending their entire life cycles, from eggs to adults, feeding on their canine hosts. All dogs are likely carriers of demodex mites, though healthy ones may never develop problems or show symptoms. But those with poorly functioning immune systems require veterinary attention to overcome the demodex.
Most dogs have demodex parasites on them, and most dogs are healthy enough to keep the mites at bay. Whether the mites become an infestation depends on the strength of a dog's immune system. For example, the parasite is most noticeable in older dogs, in dogs less than a year old and in dogs with medical conditions that require medications. This is because puppies and elderly dogs typically have suppressed immune systems, allowing the parasites to quickly spread. One obvious sign of demodex mange is hair loss, which typically begins around the face. If the hair loss is mainly restricted to one area of the body, it is known as localized demodectic mange. If numerous patches of hair loss exist on the body, it is referred to as generalized demodectic mange.
Localized demodectic mange consists of fewer than two regions of baldness and fewer than four bald spots total. In healthy dogs, localized demodectic mange will likely go away on its own. If it does not resolve itself, the mange is commonly treated using topical medications prescribed by a veterinarian. These topical medications, usually miticidal ointments, ease itching and stop inflammation of the skin by killing the parasites. Applying topical treatments can further irritate your dog's skin, as well as break finer hairs, making the condition appear worse than it actually is.
If localized demodectic mange does not clear up on its own or with use of topical medications, it will spread and become generalized. A common sign of this, besides an increase in the number and spread of bald spots, is enlarged lymph nodes. Veterinarians treat generalized demodectic mange using shampoos and insecticide dips. Weekly dips over the course of one or two months should treat the condition. Dips sometimes cause side effects such as vomiting and should be performed carefully. Oral treatments are available but should be avoided in herding breeds like collies and sheepdogs. If the mange is bad enough, bacterial skin infections may arise.
If your veterinarian diagnoses your dog with demodectic mange, it is important to isolate your dog from other pets to prevent the mites from spreading. Next, clean or replace his bedding and all items that could harbor the parasite, from toys to collars. Once your veterinarian checks your dog for mange and chooses the treatment right for him, he will have to have skin scrapes to ensure there won't be a relapse. Your veterinarian may suggest that your dog be spayed or neutered to prevent spreading the parasites to any future puppies, especially if the case is generalized.
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