The human skin, our significant interface with the environment, is the largest organ of the body. It covers the outer of the body with multiple layers of tissue for safeguarding the underlying bones, muscles, ligaments as well as the internal organs. It also serves as the first line of defense against foreign pathogens in the body immunity. The skin is classified as three layers roughly: epidermis, dermis, hypodermis. Epidermis provides a barrier to infection from environmental pathogens and regulates the water loss of the body at the outermost part of the skin. Beneath the epidermis, there keeps the dermis (or corium). This layer primarily has tough connective tissues, sweat glands, and hair follicles. The deeper layer, hypodermis, is consists of loose connective tissue and lobules of fat. Skin lesions could occur in these parts under the condition that the self-protect failed. Kinds of target molecules of the skin tissue are employed for the detection and diagnosis of skin diseases.