1.What is atopic dermatitis? Atopic dermatitis (AD), also known as atopic dermatitis, atopic eczema, genetic allergic eczema, is a kind of allergic skin disease closely related to congenital allergies. The family members often have a history of urticaria, bronchial asthma, allergic rhinitis, eczema and other allergic diseases. 2, the clinical stage of atopic dermatitis The disease is slow, recurrent, and has different clinical manifestations depending on the age. It is usually divided into infantile, childhood and adult stages. Infantile stage: about 60% of patients have the disease within 1 year of age, with more after 2 months of life. The initial lesions are pruritic erythema on the cheeks, followed by the appearance of pinhead-sized papules and papules on top of the erythema, which are densely packed into patches with indistinct boundaries and soon form vesicles, oozing and crusts after scratching and rubbing. The lesions can rapidly expand to other parts of the body, such as the scalp, forehead, neck, wrists, and flexors of the limbs. The disease may be mild or severe, and may be aggravated by certain food or environmental factors, and secondary infections may occur. Most of the children gradually improve and heal within 2 years of age; some of them develop atopic dermatitis in childhood. Childhood: Most atopic dermatitis occurs 1 to 2 years after the remission of infantile atopic dermatitis and gradually worsens, while a few may continue from infancy. The lesions mostly involve the flexors of the extremities, often limited to the elbow fossa, N fossa, etc.; followed by the eyelids, face and neck. The lesions are dark red, with lighter exudation than in infancy, often accompanied by secondary lesions such as scratch marks, and over time form mossy lesions. Itching is still very intense during this period, and a vicious cycle of itching – scratching – aggravation of the disease – increased itching – scratching again is easily formed. Adult stage: Atopic dermatitis in adolescence and adulthood after the age of 14 years, which can develop from childhood or occur directly. It occurs in the elbow fossa, N-fossa, extremities, trunk, and in some patients in the palmoplantar area. The lesions often appear as limited mossy lesions, sometimes with acute or subacute eczema-like changes, and in some patients they appear as generalized dry papules. Itching is intense, and scratching results in secondary lesions such as blood crust, scaling and pigmentation.