Sputum is formed as a result of inflammation of the respiratory tract and changes in the nature of the secreted mucus. Sputum can be classified as upper respiratory tract and lower respiratory tract based on the site of production.
Normal people produce very little sputum each day, and when inflammatory changes occur in the respiratory tract, the mucus secreted changes in character and can secrete large amounts of viscous fluid containing mucus, pathogens, inflammatory cells, shed necrotic epithelial tissue, and other objects, called sputum.
If you usually feel nasal congestion, headache, dizziness, decreased sense of smell, and other symptoms in addition to phlegm, you should consider rhinogenic phlegm caused by rhinitis. The reason for this is that there are many causes of lower respiratory tract diseases, and the color of sputum varies from cause to cause: coughing white sputum is common in bronchitis, and if yellow sputum is present, it is considered to be combined with bacterial infection. The most important thing is to have a good understanding of the nature of the disease.
To determine the cause of sputum, you need to visit the respiratory department of a regular hospital to improve laboratory tests such as chest x-ray, chest CT, blood tests, and sputum culture to determine the cause and provide timely treatment.