an unpleasant, usually reddened section of degenerating, ulcerated epidermis due to force and lack of action, and worsened by exposure to urine or any other irritating substances on the epidermis. Untreated sleep lesions can become really contaminated or gangrenous. Sleep sores tend to be a major problem for clients who're restricted to bed or a wheelchair. They can be avoided by moving the individual often, switching bedding, and keeping the skin clean and dry. Also known as a pressure sore, decubitus aching, or decubitus ulcer.