Allergic dermatitis is mostly due to an inflammatory reaction of the skin or mucous membranes after contact with exogenous substances, and usually manifests itself in the form of erythema, swelling, papules, blisters, etc., usually accompanied by itching symptoms. Scratching is unavoidable when itching is evident, thus damaging the skin barrier, leading to further aggravation of the dermatitis symptoms and gradual spreading of the rash. The spreading of the rash usually aggravates the itchiness, and in severe cases may even interfere with sleep. In addition, other factors can also trigger the spread of atopic dermatitis, such as sun exposure, excessive sweating, dry skin, as well as contact with animal fur or plants, chemicals and other sensitizing substances can aggravate skin inflammation. Eating certain foods, such as seafood, mango and other allergy-prone foods, may also cause the spread of dermatitis. Therefore, it is recommended that patients with atopic dermatitis avoid re-exposure to suspected allergenic substances, do not scratch during the onset of the disease, and avoid stimulating the skin with soap and hot water. In general, pay attention to a balanced diet, avoid eating stimulating foods and drinking alcohol, and maintain good living habits. Stay away from allergenic substances, choose skin care products carefully, and consult a doctor if allergy occurs.