Does permethrin work after the first use or second use for scabies? Does it work if you do not have a rash yet?

Works most of the ti. It can be weeks, even months, after correct treatment, for full relief from itch. Common cause for failed treatment is incorrect application. Another common cause is failure to treat all contacts. The itch is due to allergy to mites embedded in skin. After you kill the mites you are still allergic to the dead mites remaining in the skin. Permethrin should be applied to every inch from ears to toes.