Itching can be caused by nerve damage associated with diabetes or lack of vitamin B12, skin diseases, an allergy to something touching the skin or inside your body or a hidden tumor or infection. Often doctors cannot find the cause.
When more than one person in a family itches, the usual cause is scabies, a disease caused by a parasite that burrows into your skin. You usually cannot see the bug that causes scabies. Sometimes the only way that you can see it is in a piece of skin that has been removed from the body and has been placed under a microscope. You may see little bumps between your fingers, in your armpits and groin, at your belt line or on your back or chest. You also may see three or more bumps in a line. The most common treatment is to cover the entire body for 12 hours with a prescription cream containing permethrin. If you still have itching, your doctor may prescribe a single pill called Ivermectin. Check with your doctor.