The goal of this observational study is to learn about the metabolomic profile of blood and urine in children 12-17 years with asthma. The main question it aims to answer is:

• Are there metabolites in the blood and urine that are specific for asthma exacerbation? Participants already receive standard therapy as part of their regular medical care for asthma.

The study plans to enroll 100 children with a confirmed diagnosis of bronchial asthma of varying severity. Patients will be divided into groups based on disease severity (mild and severe/moderate) and stage (exacerbation/non-exacerbation). A separate group of patients receiving targeted therapy will also be included. All patients will be hospitalized in the pulmonology department. Blood and urine samples will be collected for metabolomic analysis upon admission. Patients not experiencing an exacerbation will not be re-evaluated. For patients experiencing an asthma exacerbation, blood and urine samples will be collected again after 10 days. Throughout the study, patients will receive the usual therapy prescribed by their treating physician. Treatment for exacerbations includes inhaled budesonide and ipratropium bromide/fenoterol via a nebulizer; systemic steroids may be used if indicated. All patients will undergo spirometry upon admission to the department. Patients in the acute stage will undergo spirometry at least twice, including on the 10th day, plus or minus 2 days. All patients complete the Asthma Control Test questionnaire upon admission.

Inclusion Criteria:

• Age from 12 to 17 years old
• Confirmed diagnosis of asthma
• Informed voluntary consent to participate in the study

Exclusion Criteria:

• age under 12 years
• no established diagnosis of asthma
• concomitant severe somatic, metabolic, and endocrine diseases
• patient's withdrawal of informed consent

The study will include children hospitalized in the pulmonology department of the Sechenov Center for Maternity and Childhood Care at Sechenov University.