Demodex are a cigar shaped microscopic mite which is a common cause of skin disease in dogs. It can affect cats but is less common in our feline friends. Demodicosis is most common during the ‘juvenile’ and ‘teenage’ period when a pup is rapidly growing. It can vary in severity from small patches of hair loss to severe pustular or ‘pimply’ skin disease resulting in almost total baldness. It is important for demodicosis to be distinguished from allergies as confusing the two (they both can cause secondary skin infections and baldness) can have serious consequences. The medications such as steroids which are commonly used in allergy treatment can cause demodecosis to get worse. Demodicosis in older dogs can be due to an underlying immunosuppression, such as that caused by a hormonal imbalance.
Demodicosis can be diagnosed on cytology (the examination of scrapings and samples of skin and hair under the microscope) or by biopsies (small amounts of tissue sampled and sent to the lab for microscopic analysis). It is important not to guess about the presence of demodex mites as although it can be treated, the treatment can be involved and long term (months) in some cases, so you need to be sure about the need for treatment.