Mange is a skin disease that is caused by an infestation of mites, reports VCA Animal Hospitals. It can be caused by either Demodex canis mites, known as demodectic mange, or Sarcoptes scabiei mites, or sarcoptic mange.
Sarcoptic mange is the only type that is generally contagious, according to VCA Animal Hospitals. Sarcoptic mites find a canine host and then burrow under the skin, where they feed on the dog. This causes intense itching, hair loss and discomfort. Sarcoptic mange can also be passed to humans, so it needs to be treated quickly. It is diagnosed by testing a skin scraping, but many vets begin treatment based on the symptoms to prevent further spread. It generally responds well to medication.
Demodectic mange is caused by mites that naturally live on all dogs, notes VCA Animal Hospitals. These mites are usually harmless and are controlled by the dog's immune system. Dogs with compromised immune systems may not be able to keep the population of demodex mites under control, leading to an outbreak.
Demodectic mange is probably not contagious and is often a sign of underlying health conditions, such as genetic problems or autoimmune disorders, according to WebMD. It causes hair loss, often starting around the face and ears. However, it can be found anywhere on the body and can spread. Demodectic mange does not usually cause the dog to itch, but it may cause sores that become infected, and that can lead to itchiness.