Principles Of Treatment Of Skin Diseases And Tips Abstract Skin is the largest organ of the body covering and constitutes the first line of defense. The skin protects the body from harmful agents such as ultraviolet rays and from infective organisms in the atmosphere. It has many specialized cells and structures which are divided into three layers – epidermis, dermis and hypodermis. The epidermis is the outermost layer of the skin and protects the body from the environment. The dermis