Eczema is a relatively common inflammatory reaction of the epidermis and superficial dermis caused by a variety of internal and external factors, with intense itching. There are three phases: acute, subacute and chronic. The acute phase has an exudative tendency. The chronic phase is infiltrative and hypertrophic. It is characterized by spontaneous, intense itching, polymorphic lesions, symmetrical distribution, tendency to exude, chronic course, and easy recurrence. Some patients present directly as chronic eczema. The lesions are polymorphic, symmetrical, itchy, and prone to recurrence. We should avoid external stimuli such as hot water, excessive scratching, washing and contact with potentially sensitive substances such as fur preparations. Avoid contact with chemical products such as soap, washing powder, detergent, etc. Avoid potentially allergenic and irritating foods, such as chili peppers, strong tea, coffee, and alcohol. Etiology The cause of eczema is complex and often the result of interaction between internal and external factors. Internal factors such as chronic digestive diseases, mental stress, insomnia, overexertion, emotional changes, endocrine disorders, infections, metabolic disorders, etc., and external factors such as living environment, climate change, food, etc., can affect the occurrence of eczema. External stimuli such as sunlight, cold, dryness, heat, hot water scalding and various animal fur, plants, cosmetics, soap, artificial fibers, etc. can induce. It is a delayed metamorphosis caused by complex internal and external factors. Clinical manifestations 1, according to the performance of the lesions are divided into acute, subacute, chronic three stages. (1) Acute eczema The lesions are initially most dense corn-sized papules, papules or small blisters with a flushed base, gradually fusing into patches, due to scratching, the top of the papules, papules or blisters are scratched with obvious punctate exudate and small vesicular surface with unclear edges. If secondary infection occurs, the inflammation is more obvious and can form pustules, pustules, folliculitis, boils, etc. Intense itching. It occurs on the head and face, behind the ears, distal extremities, scrotum, perianal area, etc., and is mostly released symmetrically. (2) Subacute eczema After the inflammation of acute eczema is reduced, the lesions are mainly small papules, crusts and scales, and only a few papules and vesicles are seen. There is still intense pruritus. (3) chronic eczema is often due to acute, subacute eczema repeated episodes do not heal and turn into chronic eczema; can also start that is chronic eczema. Manifestation of the affected skin thickening, infiltration, brownish red or pigmentation, surface roughness, covered with scales, or due to scratching and crusting. Itching is intense. It is common on the lower legs, hands, feet, elbow fossa, N fossa, vulva and anus. The course of the disease is variable, easy to recur and does not heal after a long time. 2, according to the extent of the lesions involved, divided into two categories of limited eczema and generalized eczema. (1) limited eczema occurs only in specific areas, that is, you can name the site, such as hand eczema, female eczema, scrotal eczema, ear eczema, breast eczema, perianal eczema, calf eczema, etc. (2) generalized eczema The lesions are many, generalized or distributed in many parts of the body. For example, coin eczema, auto-sensitive eczema, and lipid-deficient eczema. Diagnosis is mainly based on medical history, rash pattern and disease duration. In general, the lesions of eczema are polymorphic, with erythema, papules, and papules predominantly, with a central rash that is distinct and gradually spreads out to the periphery, with unclear boundaries, diffuse, with a tendency to exude, and in chronic cases, with infiltrative hypertrophy. The course of the disease is irregular, with recurrent episodes and intense pruritus.