If it is localized, use Infra-Red lamp to heat the place. Depending on the power of the lamp, place it over the affected place at a distance of about:
- Blue-lamp "Reflector of Minin" 60W or 80W: 4-5cm
- IR heating lamp 100W: 15cm
- IR heating lamp 150W: 20cm
and treat the place for 3-5min. You should feel the heat at the edge of the tolerance. As the tiny spiders and their eggs, causing scabies, are very sensitive to heat, thei should be destroyed with this procedure. The IR will penetrate to about 1-3cm (depending the power) the skin, it reaches for sure the parasites. And IR lamps do not claim to be a cure-all devices, their price is incomparable lower to the Rife machines. And still can help in many cases - from skin problems to common cold.
The suggestion from the others, to clear the environment, stays of course completely valid.
The reflector of Minin. And old USSR technology, practically very similar to IR lamps (despite the blue color of the bulb). More mild as effect, generally cheaper and with longer lifespan of the bulb:
IR lamp. Much more powerful and more easy to find. The lifespan of the bulb is the only disadvantage, but the price is still way lower than the medicines one lamp could save you: