Mange is a type of skin disease caused by parasitic mites. Because various species of mites also infect plants, birds and reptiles, the term "mange", or colloquially "the mange", suggesting poor condition of the skin and fur due to the infection, is sometimes reserved for pathological mite-infestation of nonhuman mammals. Thus, mange includes mite-associated skin disease in domestic mammals (cats and dogs), in livestock (such as sheep scab), and in wild mammals (for example, foxes, coyotes, cougars and wombats. Severe mange caused by mites has been observed in wild bears. Since mites belong to the arachnid subclass Acari (also called Acarina), another term for mite infestation is acariasis.

Parasitic mites that cause mange in mammals embed themselves in either skin or hair follicles in the animal, depending upon their genus. Sarcoptes spp. burrow into skin, while Demodex spp. live in follicles.

In humans, these two types of mite infections, which would be known as "mange" in furry mammals, are instead known respectively as scabies and demodicosis.