I. Etiology and pathogenesis The etiology of eczema is still unclear. Endogenous causes include abnormal immune function (such as immune imbalance, immunodeficiency, etc.) and systemic diseases (such as endocrine diseases, nutritional disorders, chronic infections, tumors, etc.) as well as hereditary or acquired skin barrier dysfunction. External factors such as, allergens in the environment or food, irritants, microorganisms, changes in ambient temperature or humidity, and sun exposure can trigger or aggravate eczema. Psychosocial factors such as stress and anxiety can also trigger or aggravate the disease. The pathogenesis of this disease is not clear. At present, it is mostly believed to be the result of a combination of internal and external factors based on internal factors such as abnormal immune function and skin barrier dysfunction. Both immune mechanisms such as allergic reactions and non-immune mechanisms such as skin irritation are involved in the pathogenesis. Microorganisms can trigger or aggravate eczema through direct invasion, superantigen action or induced immune response. The clinical manifestations of eczema can be divided into acute, subacute and chronic phases The acute phase is characterized by erythema, edema on the basis of corn-grain papules, papules, blisters, vesicles and exudate, the center of the lesion is often heavy, and gradually spread to the periphery, and scattered papules, papules, so the boundary is unclear. In the subacute stage, the redness and exudation are reduced, and the vesicular surface is crusted and desquamated. Chronic eczema mainly manifests as rough hypertrophy, moss-like changes, can be accompanied by pigment changes, hand and foot eczema can be accompanied by nail changes The rash is generally symmetrical distribution, often recurrent, conscious symptoms of pruritus, or even severe itching Three, laboratory tests are mainly used for differential diagnosis and screening of possible causes, routine blood tests can have eosinophilia, but also serum eosinophilic cationic protein increased, some patients have increased serum lgE The allergen test can help to find possible allergens, the patch test can help to diagnose contact dermatitis, the fungal test can identify superficial fungal disease, the scabies test can help to exclude scabies, the serum immunoglobulin test can help to identify congenital diseases with eczema dermatitis lesions, the bacterial culture of skin lesions can help to diagnose secondary bacterial infections, etc., and the histopathological examination of the skin should be performed when necessary. Fourth, the diagnosis and differential diagnosis of eczema is mainly based on clinical manifestations, combined with the necessary laboratory tests or histopathological examination. Special types of eczema are diagnosed according to clinical features, such as dry eczema, self-sensitivity dermatitis, coin-shaped eczema, etc.; non-specific cases can be diagnosed according to clinical sites, such as hand eczema, calf eczema, perianal eczema. breast eczema, scrotal eczema, ear eczema, eyelid eczema, etc.; pancystic eczema refers to eczema occurring simultaneously in multiple sites, and the severity of eczema can be scored according to its area and the characteristics of the rash. It should be differentiated from the following diseases: (1) it should be differentiated from other types of dermatitis with specific etiology and clinical manifestations, such as atopic dermatitis, contact dermatitis, seborrheic dermatitis, bruising dermatitis, neurodermatitis, etc.; (2) it should be differentiated from diseases with eczema-like manifestations, such as superficial fungal disease, scabies, polymorphic heliotrope, eosinophilia syndrome, pellagra and cutaneous lymphoma, etc.; (3) it should be differentiated from rare congenital diseases with eczema-like The main goal of treatment is to control symptoms, reduce recurrence, and improve the quality of life of patients. Treatment should be considered as a whole, taking into account both the immediate and long-term efficacy, with special attention to medical safety in treatment. 1, basic treatment: ① patient education: the need to explain the nature of the disease, possible regression, the impact of the disease on the health of the body, the presence of infectious, the clinical efficacy of various treatment methods and possible adverse reactions, etc., to guide patients to find and avoid common allergens and irritants in the environment, avoid scratching and excessive washing, the environment, diet, the use of protective equipment, skin cleaning methods should also be recommended accordingly; ② avoid triggering or aggravating factors: through detailed history taking, careful physical examination, reasonable use of diagnostic tests, carefully find a variety of suspected causes and triggering or aggravating factors, in order to remove the cause, the purpose of treatment, such as Ü dry eczema should be treated to make the skin Ü dry factors, infectious eczema should treat the primary infection, etc.; ③ protect the skin barrier function: eczema patients with damage to the skin barrier function, prone to secondary irritant dermatitis The skin barrier function is very important to protect the patient’s skin, should be selected for treatment without irritation, prevention of puff timely treatment of secondary infections, the skin dry subacute and chronic eczema with moisturizers. 2, local treatment: is the main means of eczema treatment should be based on the stage of the lesions to choose the appropriate drug formulations. In the acute stage five blisters, vesicles, exudate, it is recommended to use furnace glycolate lotion, glucocorticoid cream or gel; a large number of exudate should choose cold wet compresses, such as 3% boric acid solution, 0, 1% berberine hydrochloride solution, 0, 1% ezacrine solution; vesicles but not much exudate can be used when the zinc oxide oil. For subacute lesions, topical zinc oxide paste is recommended. Glucocorticoid cream. For chronic lesions, topical glucocorticoid ointment, hard cream, emulsion or tincture is recommended, and moisturizers and keratolytic agents such as 20%-40% urea ointment and 5%-10% salicylic acid ointment can be used in combination. Topical glucocorticoid preparations are still the main drugs used to treat eczema. Initial treatment should be based on the nature of the lesions to choose the appropriate strength glucocorticoid: weak glucocorticoids such as hydrocortisone and dexamethasone cream are recommended for mild eczema; strong glucocorticoids such as harcionide and halometasone cream are recommended for severe hypertrophic lesions; moderate eczema is recommended to choose medium-acting hormones such as tretinoin and mometasone furoate. In children, weak or medium-acting glucocorticoids are generally effective in the face and skin folds. Strong glucocorticosteroids are generally applied continuously for no more than 2 weeks to reduce acute tolerance and adverse effects. Calcium-regulated neurophosphatase inhibitors such as tacrolimus ointment. Pimecrolimus cream elbow eczema has a therapeutic effect without the side effects of glucocorticoids, and is particularly suitable for the treatment of eczema on the head, face and inter-rub areas. Bacterial colonization and infection can often induce or aggravate eczema, so antibacterial drugs are also an important aspect of topical treatment. A variety of topical preparations of anti-thrombotic drugs are available, as well as a combination of glucocorticoids and antibacterial drugs. Other topical drugs such as tar, antipruritic agents, topical preparations of non-steroidal anti-inflammatory drugs, etc., can be applied according to the situation of choice. 3, systemic treatment: ① antihistamines: according to the patient’s condition, choose appropriate antihistamines to stop itching and anti-inflammation; ② antibiotics: for those with extensive infections, it is recommended to systematically apply antibiotics for 7~10d; ③ vitamin c, calcium gluconate, etc. have certain anti-allergic effects and can be used for acute attacks into pruritus obviously; ④ glucocorticoids: – generally not advocated for routine use, but can be used for Patients whose etiology is clear and whose etiology can be dispelled in the short term, such as those caused by contact factors, drug factors or self-sensitivity dermatitis; for severe edema, generalized rash. Erythroderma and other for rapid control of symptoms to short-term application, Tan must be careful to avoid systemic adverse reactions and rebound; ⑤ Immunosuppressants: should be used with caution, to strictly control the indications – limited to other therapies are ineffective, there are contraindications to the application of glucocorticoid hormone patients with severe disease, or short-term systemic application of glucocorticoid hormones after significant remission, the need to reduce or discontinue the use of glucocorticoids. 4, physical therapy: ultraviolet therapy, including UVAI (340-400 nm) irradiation, UVA/UVB irradiation and narrow-spectrum UVB (310-315 nm) irradiation, has a better effect on chronic intractable eczema. 5, Chinese medicine therapy: Chinese medicine can be internal or external treatment, should be based on the condition of evidence-based treatment. Chinese medicine extracts such as compound glycyrrhetinic acid glycosides, tretinoin polysaccharide, etc. are effective for some patients. It should be noted that herbal medicines can also lead to serious adverse reactions, such as allergic reactions, liver and kidney damage, etc. 6, follow-up and prevention: the disease is prone to recurrence, it is recommended that patients regularly follow-up, preferably 1 week after treatment for acute eczema, 1 to 2 weeks after treatment for subacute patients, and 2 to 4 weeks after treatment for chronic patients, to evaluate the efficacy of follow-up, changes in condition, the need for further tests, and to evaluate compliance. For recurrent and persistent cases, attention should be paid to analyze the causes. The common causes are: ①Irritant factors: due to the destruction of the skin barrier function, new or weak irritants, even substances that are not irritating under normal circumstances, also become irritants. Note that therapeutic medication can also produce irritation; ② ignore contact allergens: ignore certain contact allergens in the family, occupation and hobby; ③ cross-allergy: pay attention to the cross-allergens of allergens carefully checked; ④ secondary allergy: pay attention to avoid secondary allergy to drugs (especially adrenal glucocorticoids) and chemicals (such as rubber latex in gloves); ⑤ secondary infection: destruction of skin barrier function (5) secondary infections: destruction of skin barrier function, application of adrenal glucocorticosteroids, etc., which may cause secondary bacterial or fungal infections; (6) unfavorable factors: sunlight, hot environment, continuous sweating, cold and dry can aggravate the condition; (7) systemic factors: such as diabetic patients prone to itching, secondary skin infections, etc.