Scabies, known as the seven-year itch, is a contagious skin infestation by the mite Sarcoptes scabiei.The most common symptoms are severe itchiness and a pimple-like rash. Occasionally tiny burrows may be seen in the skin. When first infected, usually two to six weeks are required before symptoms occur.cabies, known as the seven-year itch, is a contagious skin infestation by the mite Sarcoptes scabiei.