Mange is caused by microscopic mites that invade the skin of otherwise healthy animals. The mites cause irritation of the skin and a hypersensitivity reaction, resulting in itching, hair loss, and inflammation. Mange is rare in horses. There are several types of mange that affect horses, including sarcoptic mange (equine scabies), psoroptic mange (mane mange), chorioptic mange (leg mange), demodectic mange, harvest mites (chiggers, trombiculids), and straw itch mites (forage mites).