The present invention relates to a method for treating a disorder chosen from ocular Demodex, Demodex-induced blepharitis, rosacea, acne, and meibomian gland dysfunction in a patient in need thereof, comprising administering to the patient a composition comprising a therapeutically effective amount of a substance chosen from at least one of an isoprenoidal essential oil such as Tea Tree Oil; Terpinen-4-ol; (+)-Carvone; alpha-Terpineol; Cardinene; d-Carvone; l-Carvone; gamma-Terpinene; alpha-Terpinene; 1,8-Cineole; alpha-Terpineol; para-Cimene; alpha-Pinene; Limonene; (R)-(+)-Limonene; alpha-Thugene; Eucalyptol; (+)-Ledene; Cuminic Aldehyde; and Myrcene; the administration comprising contacting or scrubbing an affected area of skin or hair, or eyelid margin and lashes of the patient with the composition; also disclosed are a method for treating mange and mite infestations on a mammalian animal; and kits for in-office and at home treatments of the disorders.