These are caused by prolonged pressure to certain parts of the body when lying in bed for long periods. They are best prevented by encouraging the patient to shift position as often as possible and taking care to smooth out the creases in the bottom sheet, which could lead to localised irritation. Keep your eye open for red marks appearing at pressure points such as heels, elbows, buttock and hips. If they begin to appear inform your doctor or district nurse, before they get worse.