Keratotic scabies: A severe form of scabies that is caused by delaying treatment of the initial infestation. Keratotic scabies is characterized by mite-filled lesions covered with scabs. These lesions often become infected with bacteria such as staphylococcus. Keratotic scabies is most common in people with immune-system problems, including AIDS, diabetes, and lupus. Also known as crusted scabies.