Canine demodecosis is an inflammatory parasitic disease of dogs, characterized by the presence of a high number of mites on the hair follicles, which often leads to a secondary bacterial infection. The mite, Demodex canis, is a part of the normal funna of canine skin and is normally preset in small numbers. The mite resides in the hair follicles and sebaceous gland of the skin. Pathologic changes develop for the mite infestation when numbers exceed that tolerated by the immune system.
There are two types of Demodex infestations: localized and generalized.
Localized cases occur in young dogs usually going though puberty. This can happen anywhere from 3-18 months old. It is a mild case, usually on the face. Patches of hair lost can also occur on the limbs or trunk of the body. Most cases (90%) resolve spontaneously with no treatment. This is not a genetic problem.
Generalized cases can occur in young or old dogs. It is a severe disease that causes hair loss all over the body. As hair follicles become distended with large numbers of mites, secondary bacterial infections are common, often with rupturing of the follicles. Dogs with generalized demodex must be dipped regularly to try and kill the excessive mites. In the worst cases, the dog would have to be euthanized. These dogs are thought to have a poor immune system that is unable to fight off the excessive mites. These dogs are NEVER to be bred.