How do I know if I have scabies? Scabies is a common skin infestation caused by a human itch mite, Sarcoptes scabiei var. Hominis. You know if you have scabies mites if you experience extreme itching, rash, sores, and crusted skin. Scabies is a common skin infestation caused by a human itch mite, Sarcoptes scabiei var....