You need to get to the vet. Natural remedies may help symptoms but will NOT kill the sarcopses. Sarcoptic mange is not just contagious to other pets , but to humans as well. Mange is not species specific like lice.
First, you need to make sure it is sarcopses, and not demodex. Your dog needs a skin scraping that the vet or tech can then read under a microscope to see exactly which you are dealing with.
The best treatment for sarcoptic mange, IMO , is an amitraz dip, such as Mitaban. You doctor will prescribe what he/she feels is best. Use of an antiseborrheic/ antibacterial shampoo can help soothe the skin, and is recommended if you are using amitraz.