Mites cause scabies.
Scabies , previously known as the seven-year itch , is a contagious skin infestation by the mite Sarcoptes scabiei . Scabies is caused by infection with the female mite Sarcoptes scabiei var . The symptoms of scabies are due to an allergic reaction to the mites . It typically only occurs in those with a poor immune system and people may have millions of mites , making them much more contagious .