What causes nasal congestion?

Nasal congestion can be caused by various factors, mainly including: 1. Environmental factors: For example, a dry air environment may cause dehydration of the nasal mucosa, leading to nasal congestion. 2. Allergic reactions: Such as allergic rhinitis, caused by allergens like pollen, dust mites, and animal dander, leading to inflammation, swelling, and increased secretions of the nasal mucosa, resulting in nasal congestion. 3. Infectious factors: Viral infections such as the common cold, influenza, or sinusitis can cause swelling of the nasal mucosa and excessive mucus production, thus triggering nasal congestion. 4. Nasal diseases: For example, deviated nasal septum narrows the nasal cavity, affecting airflow; nasal polyps, as benign tumors in the nasal cavity, can also block the nasal passage, causing nasal congestion. If symptoms persist or worsen, it is recommended to seek medical attention promptly.