Compositions and methods for treating and preventing arthropod infestation are disclosed. A method of treating an arthropod infestation in a subject in need thereof, the method comprising administering topically to the subject an effective amount of either an insecticidal composition consisting essentially of at least one essential oil and a pentacyclosiloxane or an insecticidal composition comprising at least one essential oil, a pentacyclosiloxane, and a mineral oil.