Usually once. Scabies is caused by a mite that burrows into the skin and lays eggs. The eggs take a few days to hatch. Generally one application of Permethrin cream kills the mites and eggs but occasionally a second application a week later can be used to kill any mites that hatch from eggs that survive the first treatment. You should not use more than 2 applications.
Scabies. You only need to apply only once overnight and wash it in the morning.