Eczema is a common inflammatory skin disease of the epidermis and superficial dermis caused by a variety of internal and external factors. It is characterized by intense itching, polymorphic lesions, symmetrical distribution, tendency to exude, chronic course, and tendency to recur. Skin characteristics of the affected area: it can occur in any area, commonly on the face, behind the ears, flexors of the limbs, breasts, hands, scrotum, etc., with symmetrical distribution. According to the characteristics of the lesions can be divided into acute, subacute and chronic eczema. There is no clear boundary between the three, and they can be transformed into each other. Eczema can occur in any area and is often symmetrically distributed. In the acute phase, the eczema occurs on the head, ears, hands, feet, forearms, calves and other exposed areas, and in severe cases extends to the whole body; in the chronic phase, it occurs on the hands, feet, calves, elbow sockets, femurs, breasts and vulva. The cause of eczema is very complex, and genetic, immune, environmental, physiological, pharmacological are related, its manifestations are continuous, one after another, self-diffusion, and even throughout the body, but eczema is not contagious, if not healed over time, most can be self-expanded. The clinical symptoms of eczema are varied and are divided into three types: acute, subacute and chronic, depending on the performance of the lesions in the process. Acute eczema damage polymorphic, initially erythematous, self-conscious burning, itching. Following this, scattered or dense papules or small blisters appear on the erythema, and after scratching or rubbing, scratching breaks down to form vesicles and oozing surfaces. The acute inflammation decreases with time or after treatment, the lesions dry, crust and scale, and enter the subacute phase. Chronic eczema evolves from acute and subacute recurrent episodes that do not heal, or begin with chronic inflammation, often characterized by confinement to the same area for a long time, manifested by gradual thickening of the skin, deepening of skin lines, infiltration, hyperpigmentation, etc. The main self-conscious symptom is intense itching. Although eczema has the above-mentioned common clinical manifestations, there are some differences in the pattern of lesions in different parts of the eczema. For example, eczema of the external ear canal is prone to fungal infections, and breast eczema is common in lactating women, often with chafing and pain. Anal and scrotal eczema is often caused by scratching, hot water soap and acute swelling or erosion. Eczema on the lower legs often leads to ulceration, which does not heal easily. In addition to the above, there are some unusual clinical manifestations of specific types of eczema, such as infectious eczema-like dermatitis secondary to bacterial purulent skin diseases such as otitis media, ulcers, fistulas and decubitus ulcers, and autosensitive eczema caused by allergy to substances produced by the internal skin tissue of the body. Infantile eczema occurs in infancy after the first month of life and is often symmetrical on the back of the hands, extensor surfaces of the limbs and buttocks. The lesions are shaped like coins of coin-shaped eczema. The etiology and pathogenesis of eczema is quite complex, involving a variety of internal and external factors. It is a late-onset allergic reaction that occurs in the skin. The disease often occurs in individuals with allergic qualities. Anyone with this quality is more prone to allergic reactions to various allergenic substances inside and outside the body, such as proteins in food, especially fish, shrimp, eggs and cow’s milk, as well as chemicals, plants, animal leather and feathers, parasites in the intestinal tract, and foci of infection. Some even physical stimuli such as sunlight, wind and heat, and cold can induce eczema. In addition, the occurrence of eczema, sometimes may also have some relationship with neurological dysfunction, endocrine disorders, digestive disorders, intestinal diseases, metabolic abnormalities, etc. In short, the onset of eczema is the result of the interaction of various factors. Clinically, it can also be seen that adherence to physical exercise or changes in the environment, so that eczema lesions reduce or naturally subside. The reasons for the ease of recurrence are closely related to the increased sensitivity of the patient and the multiple sources of allergenic substances. The name of the disease varies from site to site in Chinese medicine, for example, “dipping sores” is equivalent to generalized eczema, “facial travel wind” is equivalent to facial eczema, “whirling ear sores” is equivalent to ear eczema, and “nipple wind” is equivalent to eczema. The “nipple wind” is equivalent to nipple eczema, the “umbilical sore” is equivalent to umbilical eczema, the “hydrangea wind” and “kidney capsule wind” are more than scrotal eczema, and the “four bends wind” is equivalent to eczema of the scrotum. “Some palm eczema is mainly manifested by cracking, and the heavy ones can crack the skin and flesh, and the itch is so unbearable that even the hands cannot bend and curve, which is called cracked eczema. The “wet polyp” is equivalent to calf eczema, also known as bruised eczema. “Anal ringworm” is equivalent to anal eczema. According to the ancestral medicine, eczema is due to the endowment of intolerance, wind-heat, external wind evil, wind-damp-heat evil fighting each other, soaked skin and become. Among them, “dampness” is the main factor. Because dampness is sticky, heavy and changeable, the disease is prolonged and variable in form. Chronic eczema is caused by deficiency of blood and damp heat, resulting in blood deficiency and yin injury, dryness and wind, wind-dryness and damp-heat stagnation, and loss of skin nourishment. The symptoms of eczema in the palm of the skin open flesh, itching, even the hand can not bend “and other symptoms [diagnosis and differentiation] mainly based on the history and clinical features, the diagnosis is easier. Acute eczema rash is polymorphic, symmetrical distribution, tendency to exudate; chronic type lesions are mossy; subacute damage between the above two. Itching is intense; recurrence is easy. The diagnosis of specific types of eczema should be noted for their unique clinical symptoms and is not difficult. Chronic eczema needs to be differentiated from neurodermatitis, which is characterized by pruritus followed by a rash. The lesions are dry, generally non-exudative, and non-pigmented. The lesions are dry, generally non-exudative and non-pigmented. They are more likely to occur on the neck, sacral region and extensor surfaces of the limbs. It can tolerate a variety of drugs and physical and chemical stimuli. General treatment] There is no specific treatment for eczema in Western medicine, and symptomatic treatment is mostly used. The topical dosage form depends on the performance of the clinical lesions, such as erythema and swelling, exudation should choose the solution cold wet compress, erythema, papules, available lotion, emulsion, mud cream, oil, etc.; blisters, vesicles need to use oil; performance of scales, crusts with ointment; if moss-like changes, more choice of mud cream, ointment, emulsion, coating agent, tincture and hard cream, etc. The cause of the disease should be found and removed as much as possible, pay attention to adjusting the diet, avoid eating spicy and stimulating food, avoid eating allergenic items, such as alcohol, seafood and shellfish should be prohibited, and a light diet is preferable.