Recently, 5-year-old Xiaoxing visited a pediatric clinic for "repeated coughing for more than a month". His mother saw the doctor anxiously and said, "Doctor, my child has been coughing repeatedly for a month. He coughs noticeably at night and in the morning, and feels a lot of phlegm in his throat. I have checked his blood and chest X-ray before, but did not find any major problems. I have taken cough suppressants and phlegm resolving drugs, but they are not very effective. What is going on?" The doctor found that Xiaoxing's nasal mucosa was significantly swollen, and his throat wall had a large yellow nasal discharge hanging like a waterfall. There was no obvious abnormality in both lungs during auscultation. So he told the parents, "Don't worry, this is cough caused by nasal reflux, which is upper airway cough syndrome". What is Upper Airway Cough Syndrome? Upper airway cough syndrome is a clinical syndrome characterized by cough as the main clinical manifestation, caused by nasal diseases such as rhinitis and sinusitis, where secretions flow back to the nasal area and throat, directly or indirectly stimulating cough receptors. Previously known as "postnasal drip syndrome". What are the common causes? (1) Chronic rhinitis: Allergic rhinitis is the most common. When children come into contact with allergens such as pollen, dust mites, and animal hair, the nasal mucosa will experience an inflammatory response, producing a large amount of clear nasal discharge. The nasal mucus will flow backwards, stimulating the throat and causing coughing. In addition, infectious rhinitis is not uncommon, as repeated viral and bacterial infections can cause nasal mucosal congestion, edema, increased secretions, and coughing. (2) Chronic sinusitis: Children with underdeveloped sinuses have relatively large sinus openings and narrow nasal passages. Once infection occurs, inflammation is prone to spread. Therefore, many children with rhinitis are prone to developing sinusitis, with increased purulent secretions in the sinuses that cannot be discharged smoothly and can flow back to the throat, stimulating coughing. (3) Adenoid hypertrophy: Adenoid tissue is located in the nasopharynx and undergoes physiological hyperplasia during childhood. When repeatedly stimulated by inflammation, adenoids can become excessively enlarged. Therefore, children with chronic rhinitis sinusitis often have adenoid hypertrophy, which not only blocks the posterior part of the nasal cavity, affecting nasal ventilation, but also leads to poor drainage of nasal secretions, resulting in coughing. What are the characteristics of cough in upper airway cough syndrome? It is mostly a long-term chronic cough that lasts for more than 4 weeks. Coughing is more pronounced in the morning and at night when lying flat, because the position changes in the morning, and the secretions accumulated in the nasal cavity and throat are more likely to stimulate cough receptors. When lying flat at night, secretions are more likely to flow back to the throat. Some children may cough with a "squeak" sound, similar to clearing their throat. In addition to coughing, most children will have symptoms of nasal congestion and runny nose. Some children always have the movement of "sucking nasal mucus". Allergic rhinitis is mostly a watery nasal mucus, while infectious rhinitis or sinusitis is mostly a viscous or purulent nasal mucus. In addition, children with combined adenoid hypertrophy may also exhibit symptoms such as mouth breathing and nighttime snoring. Long term mouth breathing may affect the appearance of adenoid features such as protruding upper incisors and thickened lips in children. How to treat upper airway cough syndrome? (1) Etiological treatment: Take corresponding treatment measures for different etiologies. For allergic rhinitis, it is important to avoid contact with allergens and use medication under the guidance of a physician to alleviate allergic symptoms and reduce mucosal inflammation. If it is infectious rhinitis or sinusitis, choose the appropriate medication according to the type of pathogen for treatment. Individuals with severe adenoid hypertrophy should seek medical attention from an ear, nose, and throat specialist to determine if surgical treatment is necessary. (2) Symptomatic treatment: Rinse the nasal cavity with physiological saline or saline solution to remove nasal secretions, allergens, and inflammatory mediators, reduce nasal mucosal edema, and improve nasal ventilation and drainage. (3) Daily care: Pay attention to keeping indoor air fresh and humid, use air humidifiers, sun dry bedding frequently, and wear masks when going out to reduce exposure to allergens; Avoid exposure to second-hand smoke and irritating gases; Encourage children to participate in more outdoor activities, enhance their physical fitness, and prevent respiratory infections. (New Press) (Song Lin, Chief Physician of Pediatrics at Beijing Tsinghua Chang Gung Hospital)