Regularly applying soap to these areas can cause the mucosal lining in these areas to become dry and unhealthy. A chronically dry mucosal lining can lead to a number of uncomfortable health conditions, such as anal fissures, lichen sclerosus, chronic inflammation, and a tendency to experience infections. If you use soap to clean your body, you should limit its contact to your skin. Your skin is lined with sebaceous glands that secrete an oily substance called sebum, which serves to keep your skin waterproof and resistant to infection by undesirable microorganisms. Typically, the presence of sebum prevents soap from drying out skin to a point where significant health challenges can arise.