Mange ( /ˈmeɪnʒ/) is the common name for a class of skin diseases caused by parasitic mite. Since mites also infect plants, birds, and reptiles, the term "mange", suggesting poor condition of the hairy coat due to the infection, is sometimes reserved only for pathological mite-infestation of non-human mammals. Thus, mange is a term used to describe mite-associated skin disease in domestic animals (cats and dogs), in livestock (such as sheep scab), and in wild animals (for example, coyotes, cougars, and bears). Since mites belong to the arachnid subclass Acari (also called Acarina), another term used to describe mite infestation is acariasis.

Parasitic mites that cause mange in mammals embed themselves either in 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 otherwise be known as "mange" in furry mammals, are instead known (respectively) as scabies and demodicosis. However, the mites that cause these diseases in humans are closely related to those that cause the mange in other mammals.