Mange, maynj, is a contagious skin disease that certain types of mites cause in dogs, cats, sheep, horses, goats, and swine. The mites usually cause mange in animals that are ill, dirty, or neglected, or that live in crowded conditions. Mange occurs when the mites burrow into the skin of animals, causing an irritation. Animals with mange experience severe itching and have areas of redness and swelling. As the disease progresses, the condition of the sores and areas of swelling worsens and patches of hair or wool fall out. Continuous scratching may cause open sores.