What causes prolonged coughing in children?

Patient's question:

Gender: Female
Age:
Detailed medical condition and consultation purpose: Is my daughter's illness bronchitis?
Or pneumonia?
Or is there a problem with the thymus?
Or some other disease?
Duration of the current illness: Over a month
Current general condition: Coughing (producing white, clear sputum), poor complexion, not as good as usual

Doctor's answer:

According to your description of the symptoms, the baby should be considered to have bronchopneumonia. Mild bronchopneumonia usually heals quickly with appropriate treatment and can be treated in an outpatient setting or at home. Treatment with traditional Chinese medicine methods such as ventilating the lungs, clearing heat, and resolving phlegm, or with antibiotics, often leads to recovery within 1 to 2 weeks. For older children with milder conditions, penicillin can be used. If lymphocyte levels are high, Chinese herbal medicine preparations can be used for antiviral treatment. If the symptoms are more severe, hospitalization should be considered.
Maintain adequate fluid intake and provide liquid foods such as breast milk, cow's milk, rice porridge, vegetable water, and fruit juice. Vitamin C, A, D, and complex B vitamins can also be supplemented. Calcium should be given concurrently. For longer-lasting cases, it is important to strengthen nutrition to prevent malnutrition.