This study looks at how well and how safe fluticasone propionate nebulized suspension works in babies aged 0 to 24 months who have acute wheezing.

Investigators will compare it to budesonide nebulized suspension, another approved inhaled steroid.

About 240 babies will join. Participants will be put into two groups by chance (1:1 randomization):

One group gets fluticasone propionate 0.5 mg twice a day by nebulizer The other group gets budesonide 1 mg twice a day by nebulizer Treatment lasts 5 to 7 days. Investigators will check breathing symptoms (wheezing, cough, phlegm, wheeze sounds in lungs) every day during treatment.

The study will check if fluticasone works as well as budesonide (non-inferiority) and may also check if it works better. Safety will be watched closely, including side effects, general health, and lab tests.

This study will help doctors know if fluticasone propionate nebulized suspension is a good treatment option for young babies with wheezing.

Inclusion Criteria:

• Age: 0-24 months, gender unlimited;
• Clinical diagnosis: infantile wheezing, with the diagnostic criteria referring to Zhu Futang Practical Pediatrics (9th Edition);
• Inpatients with acute clinical manifestations including wheezing, cough, sputum, and bilateral lung wheezes (wheezing and wheezes are mandatory), and the total score of wheezing symptoms and signs (including wheezing + wheezes) ≥ 2 points;
• The onset of the above wheezing symptoms is within 72 hours;
• The guardian of the subject consents and signs the informed consent form.

Exclusion Criteria:

• Children with a clear diagnosis of congenital heart disease (excluding patent ductus arteriosus or patent foramen ovale), primary immunodeficiency, bronchopulmonary dysplasia, bronchiectasis, foreign bodies in the bronchi, pulmonary tuberculosis, or other congenital malformations that may cause wheezing diseases;

• Those with comorbid primary diseases of the circulatory system, digestive system, urinary system, endocrine system, hematopoietic system, and immune system;

• Those with severe respiratory insufficiency;

• Those allergic to the study drugs;

• Those who have received systemic hormone therapy during the current episode of the disease are not eligible for enrollment;

• Before enrollment, any one of the laboratory test indicators meets the following criteria: Alanine Aminotransferase (ALT) and Aspartate Aminotransferase (AST) > 2 times the Upper Limit of Normal (ULN) (refer to the normal reference range of laboratory tests in the participating research center); Serum Creatinine (Scr)

  • the Upper Limit of Normal.

• Those who have participated in other clinical trials within the past 90 days are not eligible for enrollment;

• Those who the researcher deems unsuitable for participating in the clinical trial are not eligible for enrollment.

De-identified individual participant data (IPD) will not be shared due to institutional data policy and participant privacy protection requirements.