The skin is the largest organ of the human body, wrapped around our whole body, and the closest contact with the outside world, so the skin has become the body’s first line of defense against the invasion of harmful substances from the outside world. Some internal tissues and other systemic diseases can also be reflected in the skin. People’s physical health from their skin often can also be shown, the normal skin surface appears soft and smooth, even skin color, touch the soft and elastic. The color of the skin varies greatly according to race, age, gender and distribution site. Skin consists of epidermis, dermis, subcutaneous tissue, skin appendages, blood vessels, lymphatic vessels, muscles, nerves, etc., which can be described as a complex structure. Seemingly thin skin has a mechanical stimulation, physical damage, chemical damage, microbial invasion of the protective effect; there are sensory effects, thermoregulation, secretion and excretion, the absorption of certain substances such as drugs, water, important metabolic effects, as well as regulating the role of immunity and so on. When suffering from certain systemic diseases, there will be some abnormal changes in the local or general skin and even hair, mucous membranes and other places, for example, many allergic reactions triggered by drugs, food, endocrine disorders caused by changes in skin color, shape and so on. These changes remind us that certain diseases should be examined early, diagnosed and treated early, so that the skin really plays an important role as a “health indicator”. What diseases should I see a dermatologist for? Some people think that skin disease is nothing more than some spots on the skin, itchy, painful, and then serious is a little blood, some pus, in fact, it is not. Skin as the body’s largest organ, its subtle changes are closely related to the external stimulus visceral diseases. We know that the human circulatory system, respiratory system, digestive system and endocrine system and other diseases may appear successively skin symptoms, and some occupational skin diseases, infectious skin diseases and sexually transmitted diseases of the skin is more we have witnessed. Therefore, no matter what kind of disease, in the absence of clarification, as long as there are skin symptoms, you should immediately go to the dermatology department first. Since ancient times, there has been “internal medicine does not treat asthma, surgery does not treat ringworm”, a phrase that breaks down the “ringworm” as a representative of the difficult treatment of skin diseases. In a word: Where the skin, mucous membranes, nails, hair diseases and sexually transmitted diseases, can see, touch or feel the skin rash, papules, nodules, water boils, wind masses, scales, vesicles, ulcers, chafing, redundancy, atrophy, mossy changes, etc. and itching, numbness, pain, etc. should be to the regular hospitals dermatology department to accept the science of examination, diagnosis, treatment, self-governance and informal treatment is often delayed! The disease.