Demodex canis is one the major mites causing mange in dogs. It is thought that small numbers of Demodex canis are part of the normal flora of canine hair follicles. Although the exact pathogenesis is not understood, it is generally accepted that there is a specific abnormality of T cell immunity which allows proliferation of the mites in young dogs. Diagnosis is by demonstration of increased numbers of adults or immature stages of Demodex canis on skin scrapings and hair pluckings.
Sarcoptes scabiei is one of the major mites causing mange in dogs. This parasite is host specific but can cause disease in aberrant hosts including humans. Sarcoptes is an obligate parasite with the entire 21-day life cycle occurring on the host. Infestation is associated with intense pruritus. Alopecia, papules and crusts with secondary self-trauma occurs primarily on the pinna, elbows and hairless areas. Diagnosis may be difficult even after multiple skin scrapings and a presumptive diagnosis is often made by response to therapeutic trial.