Skin is the largest organ in your body and the cells are constantly replaced (from the inner parts of the skin to the outer parts). This constant exchange of the dead cells with new ones creates a protective layer on the surface. This layer protects your skin and body from bacteria, viruses, etc. Hair, nails, and glands are a part of the skin. Due to skin's numerous function in excretion, nutrition, regulation of temperature, etc., there are numerous conditions associated with it.