Recurrent reepiratoug infectine is defined as having more than 5-7 recurrent upper respiratory tract infections or more than 2-3 bronchitis or pneumonia in a year. The incidence is higher in infancy and early childhood. In recent years, it has attracted the attention of pediatricians. 1. The causes of occurrence may be related to the following factors: ① Primary or secondary immunodeficiency. ② Micronutrient deficiency, such as zinc deficiency or deficiency, children with thymus and spleen atrophy and a significant decrease in the number of T cells. Insufficient iron, magnesium, calcium and phosphorus can directly affect the phagocytosis and bactericidal power of macrophages and weaken the ability of respiratory ciliated epithelial cells to eliminate pathogens and allergic particles. ③Congenital malformations, such as congenital abnormal cilia function sign, congenital metaphyseal phagocytosis, congenital pulmonary dysplasia, congenital pulmonary cysts, etc. ④Chronic lesions, such as recurrent chronic tonsillar attacks, bronchiectasis, etc. ⑤ Other: such as malnutrition, abnormal protein loss, including nephropathy, protein-losing enteropathy, skin injury, etc. 2. Clinical manifestations and diagnosis The disease can develop throughout the year, with winter and spring being the most prominent. Fever may be present or absent, with symptoms and signs such as recurrent upper respiratory tract infections and bronchitis pneumonia. According to the diagnostic criteria established by the Chengdu Conference in 1987: Number of episodes of upper sensation: 0-2 years old 7 times/year, 3-5 years old 6 times/year, 6-12 years old 5 times/year Number of episodes of lower sensation: 0-2 years old 3 times/year, 3-5 years old 2 times/year, 6-12 years old 2 times/year Note: ① The first time of upper sensation is at least 7 days before the second time. ②If the number of upper sensation is not enough to add the number of lower respiratory tract infections, and vice versa, it is established and needs to be observed for one year. 3.Treatment: General measures: A pediatric respiratory specialist clinic should be established and managed centrally with a view to obtaining reasonable and timely treatment. Those with low immune function can be treated with immune-enhancing therapy. Gammaglobulin, for children with hypogammaglobulinemia, commonly used dose 25mg/kg, 1/2 to 1 month once, intramuscular injection. Plasma therapy Immunoglobulin, complement, and conditioner can be supplied, 10 ml/kg, intravenously once a month. Transfer factor 2 ml per injection, subcutaneously. Injected on the inner side of the upper arm. Once a week for 3 months as a course of treatment. Thymidine 2-3 mg per time, 3 times a week by subcutaneous injection on the inner side of the upper arm. 3-6 months as a course of treatment. Levamisole, 1-1.5 mg/kg/day, divided into 3 oral doses, 2 days/week, 3 months as a course of treatment. Micronutrient supplementation In zinc deficiency, zinc sulfate or gluconate preparations can be used, 5mg/kg per day for two weeks as a course of treatment, generally applied for 2-3 courses of treatment. Other deficiencies such as iron, magnesium, calcium and phosphorus should be treated according to the conventional treatment amount.