Wheezing occurs in 1/3 of children before the age of 5 years Wheezing is a common respiratory symptom in infancy and early childhood with a diverse and heterogeneous etiology. Wheezing in infants and children is by far one of the most common reasons for visits and hospitalizations. We often encounter children who are discharged from the hospital with wheezing and then re-visit the hospital with a wheezing episode less than a week later. This phenomenon is particularly evident in the winter months. Epidemiological data show that 1/3 of children <5 years of age have had at least one episode of wheezing, and recurrent wheezing in children 5 years of age and younger is a very common clinical problem faced by pediatricians. It is well documented that about 2/3 of wheezing in infants and children disappears by 6 years of age, while the remaining 1/3 have recurrent episodes and most progress to asthma. A large multicenter international study from the Americas and Europe showed that the incidence of episodic wheezing (<3 wheezing episodes) in infants and children up to the age of 1 year ranged from 14.9% to 38.6%, and the incidence of recurrent wheezing (≥3 wheezing episodes) ranged from 12.1% to 36.3%. Among them, the highest rate of consultation and re-diagnosis of recurrent wheezing was observed in children under 5 years of age, especially in infants and children under 1 year of age. There is increasing evidence that risk factors for wheezing under the age of 1 year also influence wheezing episodes and persistent wheezing in preschool children. Therefore, identifying the cause of wheezing in infants and children is essential to prevent persistent wheezing, and early and effective interventions for wheezing in infants and children can reduce the likelihood of developing childhood asthma later in life. Viral infections are common causes The common causes of recurrent wheezing in infants and children are asthma and capillary bronchitis. The risk of developing persistent asthma in children 5 years of age and younger can be assessed by the Asthma Prediction Index (API). Primary risk factors include the following: parental history of asthma, physician-diagnosed atopic dermatitis, and a basis for sensitization to inhaled allergens. Secondary risk factors include: evidence of food allergen sensitization, peripheral blood eosinophils ≥4%, and wheezing unrelated to colds. If the API is positive, then standardized treatment for asthma is recommended. Many infants and children with wheezing are associated with viral infections, and airway hyperreactivity persists for at least 3 weeks after infection, or up to 6-8 weeks in some children. Children with capillary bronchitis have coughing and wheezing symptoms in the acute phase and recurrent episodes of coughing and wheezing continue after cure. Luo Yunchun et al. found that 68.20% of children with capillary bronchitis had recurrent wheezing even after the acute phase was cured, and wheezing episodes were most frequent 1 to 2 years after the disease, with the most frequent being more than 10 times. Mycoplasma infection is also an important cause of wheezing. Wheezing in infants and children is also associated with prematurity, parental smoking, foreign bodies in the airway, gastroesophageal reflux, bronchial lymphatic tuberculosis, and immune deficiency. Aggressive treatment is needed during all episodes In infants and children, wheezing should be treated aggressively at the time of the episode, regardless of the cause. Inhaled glucocorticoids (ICS) are currently common and effective drugs for the treatment of chronic airway inflammation. ICS is the initial treatment of choice for the control of wheezing in children ≤5 years of age. 2014 Expert Consensus on the Use of Glucocorticoid Nebulized Inhalation Therapy in Pediatrics recommends that in children with severe wheezing, a combination of budesonide suspension (1 mg/dose) and bronchodilators (β2RA, M-blockers) should be given by inhalation. If the condition requires, it can be given once every 20 minutes for 3 times, and systemic glucocorticoids such as injectable methylprednisolone 1~2mg/kg・d or oral prednisolone 1~2mg/kg・d for 1~3 days. With the remission of the disease, the type and dose of drugs remain unchanged, and the interval of inhalation can be gradually extended to 4, 6, 8 to 12 hours. For children with moderate wheezing in the acute phase, the same combination of drugs mentioned above should be given 2 times/d for 2-3 d. Nebulized inhalation treatment for infants and children in remission who are <3 years of age but are predicted to be at high risk of developing asthma should strive for long-term budesonide suspension nebulized inhalation at a dose starting at 1 mg/d and gradually decreasing until the minimum effective maintenance dose is adjusted every 1 to 3 months. The regimen is individualized and given for 3, 6, 9 or 12 months of inhalation as appropriate.