1, itching scratching cycle: itching is the main symptom of atopic dermatitis, the exact mechanism is not clear, but clothing friction, allergic reactions, high ambient temperature, sweating, mood irritability, etc. can cause or aggravate itching. Itching leads to scratching, and scratching promotes the release of inflammatory mediators, which in turn aggravates itching, so that itching – scratching that forms a vicious circle. 2, dry skin itch cycle: atopic dermatitis patients with dry skin, sebum secretion decreased, and composition changes, unsaturated fatty acids increased and cholesterol levels decreased, so the loss of transdermal water increased, the skin is dry, rough, flaky. This skin has a decreased itch threshold and is less tolerant to various stimuli, thus increasing the chance of itching. Flaking and itching often lead patients to excessive washing or hot water scalding, resulting in further drying of the skin, forming a vicious cycle. 3, eczema super-infection cycle: atopic dermatitis patient’s skin lesions are a good medium for bacteria, viruses, fungi and other microorganisms, atopic dermatitis patient’s skin lesions and normal skin can be detected Staphylococcus aureus. Staphylococcus aureus can cause persistence or aggravation of lesions through direct toxin action, superantigen activation of lymphocytes or type I metaplasia. Therefore, in the care of children with atopic dermatitis, parents should pay attention to these factors in order not to aggravate the clinical symptoms of the child.