What Causes Mites in Dogs?

Mites normally live in the skin and hair follicles of dogs without producing symptoms. But when the mite population explodes due to exposure to an infected dog, a weakened immune system, stress or disease, the infestation produces a serious condition called mange. Mites are parasites, part of the Arachnida class of bugs that includes ticks and spiders. According to the website Living with Bugs, mange "is a very serious condition and should be treated. The stress brought on by intense itching and the secondary bacterial infections caused by wounds opened by scratching can be fatal."

  1. Immunodeficiency

    • In healthy dogs, the immune system works nonstop to conquer viruses, bacteria and other threats from causing illness. Dogs with suppressed or deficient immune systems can't fight these invaders efficiently. When the immune system cannot prevent the spread of mites, parasites mate on the skin. The female burrows into the dog's epidermal skin layer and lays eggs that hatch within four to eight days, overpopulating the host quickly. Mites take nutrition from the dog's blood serum and secrete a substance that further reduces the dog's ability to fight them off.

    Exposure

    • Sarcoptic mange mites cause highly contagious mange that can be transferred between dogs, cats and humans when the mites move from one host to another. If pets share sleeping space or if dogs share the bed or the furniture with the family, everyone will start scratching. These mites are hard to diagnose; the microscopic parasite can hide in the traditional skin scraping taken by a veterinarian to detect their presence.

    Other Diseases

    • Demodectic mange mites almost exclusively affect dogs under 18 months old. Puppies acquire these mites from the mother, and they live naturally in hair follicles without causing problems. However, according to Mar Vista Vet, if demodex mites infest older dogs and produce mange, veterinarians should suspect that a more serious disease may also be present. Cancer, infectious hepatitis, liver disease or kidney disease can give demodex mites the upper hand, allowing them to flourish unchecked to wreak havoc on a dog's skin. Veterinarians typically order a more in-depth medical analysis to detect other disease processes.