Demodicosis is a non-contagious parasitic skin disease caused by a mite (Demodex sp.) that normally inhabits your pet’s hair follicles. A healthy immune system ensures that the mite population remains under control. Demodex mites may over-populate in the skin of young animals with developing immune systems and in immunocompromised pets. Symptoms of demodicosis may be as mild as patchy hair loss and may progress to generalized hair loss and itchiness. Diagnosis of demodicosis is based on history, physical examination findings, and identification of numerous microscopic Demodex mites from a skin scraping. Older patients diagnosed with demodicosis require more extensive testing (blood tests, imaging) to look for a cause of the compromised immune system (e.g.: Cushing’s disease, cancer, chronic illness). Treatment for demodicosis includes: 1) topical and/or oral medications to reduce the numbers of Demodex mites, 2) antibiotics and/or antifungals to resolve secondary infections, and 3) therapy for the underlying primary disease in immunocompromised patients.