The skin is the body's largest organ. It covers and protects the entire surface of the body. It continues inside the body in a modified form called mucous membrane, which lines the bladder, lungs, vagina, intestines, nose and mouth. Disorders of the skin and mucous membranes can be simply irritating, or they can become dangerous by altering these protective tissues and allowing infection to enter the body. If you suffer from any of these disorders, use the resources on this page to find relief.