Scabies is an infestation of the skin caused by the human itch mite. Scabies is very infectious and is spread by direct contact with someone who is infected by the human itch mite. The length of time it takes scabies to heal depends on a couple of factors. First of all, with treatment, scabies will continue to itch for about two to four weeks. If there is new rashes continuing to appear, then the scabies may last for an indefinite amount of time. If the treatment works, then it could be a lot less than that. It just depends on how effective the treatment for scabies is for each person.