Demodicosis

This 10-year-old Daschund-mix was evaluated for itching, crusting and patches of hair loss that started after prednisone had been given for back pain.  Additional steroids had been given for itching, but crusting of the skin had worsened.  Microscopic evaluation of the skin’s surface revealed a severe secondary bacterial infection.  Immune-suppression from steroids could have caused the infection and were withdrawn.  Antibiotics gradually improved the skin, but the feet remained itchy and inflamed.  Skin scraping revealed numerous demodex mites.  Demodex is a microscopic parasite that can be found normally in small numbers on the skin.  Demodicosis is a disease that occurs when a compromised immune system allows the mites to proliferate out of control.  It is most commonly seen in puppies, because their immune system is immature.  In this case, immune-suppression from steroids allowed the mites to multiply and led to a severe secondary infection.