The concentration of permethrin in creams used to treat scabies is 5 percent, according to WebMD. One of a class of chemicals known as synthetic pyrethroid insecticides, permethrin closely resembles pyrethroids, which are naturally occurring insecticidal chemicals found in chrysanthemum plants, as explained by the Pesticide Management Education Program at Cornell University. Pyrethroids kill insects by quickly paralyzing their nervous systems.
Permethrin is an ideal treatment for scabies, according to the Centers for Disease Control and Prevention. The drug is safe and effective when properly applied, and it is approved for use in children who are at least 2 months old. It kills both adult lice and lice eggs, but two or more applications about one week apart are often needed to kill all of the lice in an infestation.
Scabies is a very contagious skin condition that causes severe itching and a red, raised, blistery rash, as MedicineNet describes. It is an allergic reaction to an infestation caused by the parasite Sarcoptes scabiei, a tiny mite that is about 1/3 millimeter in length.
The most common mode of transmission is direct skin-to-skin contact. However, since the scabies mite can survive for up to 36 hours off the body of a host, it is also possible to contract scabies from the towels, bedding or clothing of an infested person, according to KidsHealth.