Professor Kwon Hyeok-soo: "Don't Force Phlegm Out; Use 'huff cough' Instead"

Many people suffer from incessant coughing and a sensation of something stuck in their throat whenever the seasons change. It is easy to neglect it, thinking it is simply a cold, but if a cough persists for more than 3 weeks, it may be another signal being sent by the body. Professor Kwon Hyeok-soo of the Department of Allergy at Asan Medical Center appeared on the YouTube channel 'A Pharmacist's Story About Medicine' to explain in detail the causes of chronic cough, effective phlegm discharge methods, and management techniques that can be practiced in daily life.

Coughing that lasts more than 3 weeks, 'nerve sensitivity' is the key cause

Generally, a cough caused by a cold stops within 2 to 3 weeks. However, for chronic coughs that last beyond 3 weeks and continue for more than 8 weeks, one must look for causes other than a simple cold. Professor Kwon Hyeok-soo defines the core mechanism of coughing as 'nerve sensitivity.' The itchy sensation that triggers a cough occurs because the cough nerves have ultimately become excessively sensitive.

Four main causes of chronic cough can be identified. First is 'postnasal drip (upper airway cough syndrome),' where nasal mucus flows down the back of the throat due to rhinitis. Second is 'asthma,' which is accompanied by bronchial inflammation and spasms; third is 'eosinophilic bronchitis.' Lastly, 'gastroesophageal reflux disease' can be a cause. Professor Kwon explained, "The reason for coughing is that the cough nerves located in the nose, bronchi, esophagus, and even the ears have become sensitive due to inflammation or damage."

In particular, many patients worry about lung cancer or tuberculosis when they cough, but in reality, it is often 'sensory neuropathic cough' where the nerves have become sensitive. If a cold virus damages the cough nerves and they enter an irreversible state, coughing can persist for 1 to 2 years. In this case, consistently taking cough medicine to soothe the sensitized nerves can be the only treatment, just as much as treating a specific disease. Professor Kwon added, "Rather than unconditionally linking a cough to a specific disease and feeling fear, one must recognize that in some cases, the cough medicine itself is the only treatment to manage the nerves."

Trying to spit out phlegm can damage the throat further... Tips for 'huff cough' and 'swallowing'

When people feel phlegm stuck in their throat, many cough forcefully with a 'gagging' sound. However, Professor Kwon warns that such actions can actually be harmful. When coughing, air is expelled at a speed of 80 km/h, and at this time, the vocal cords can receive strong stimulation, causing them to swell red or even burst blood vessels. Furthermore, the act of coughing itself stimulates the surrounding nerves more, creating a vicious cycle that invites more coughing.

Then how should phlegm be managed? First, for a light sensation of something stuck or a small amount of phlegm, it is actually better to swallow it. The yellow color of phlegm is merely the color of the enzyme (myeloperoxidase) secreted by white blood cells, which are our body's immune cells, and is not a toxic substance that entered from the outside. Since swallowed phlegm is digested by stomach acid, there is no need to worry. Professor Kwon advised, "We unknowingly swallow about 200ml of postnasal drip a day, and since the amount of phlegm is much less than the amount of bacteria in saliva, there is no need to damage your throat by trying to spit it out."

However, if phlegm deep within the bronchi must be discharged, he recommends the 'huff cough,' which does not irritate the throat. This is a method of blowing out air strongly through the mouth like a 'huuu~' sound. It involves taking a deep breath as if you are trying to blow out 20 candles in front of you at once, then opening your mouth and pushing the air out strongly. Repeating this method several times will cause the phlegm deep in the bronchi to gradually move up. The key is to repeat this using about 50 to 70% of one's strength rather than doing it too hard. Additionally, it helps to distract the nerves by drinking water, or using candy or gum when a cough comes up.

If postnasal drip is suspected, utilize 'nasal irrigation' and 'nasal steroids'

If the cause of the cough is postnasal drip due to rhinitis, nasal care is the key to solving the cough. Professor Kwon also presented a self-test method to identify postnasal drip. You may suspect postnasal drip if you frequently have nasal discharge, feel the sensation of phlegm increasing significantly when lying down, or if your voice often becomes hoarse. In particular, if you feel something rushing down when you sniff strongly, there is a high possibility that inflammation and secretions in the nasal mucosa are stimulating the cough nerves.

In such cases, reducing the inflammation and secretions of the mucosa through nasal irrigation, or using nasal steroid sprays according to a specialist's prescription, can be of great help in alleviating the cough. Professor Kwon emphasized, "If the cough does not stop, rather than unconditionally linking it to a specific disease and feeling fear, one should find the location of the inflammation through accurate examination and receive treatment to manage the sensitized nerves."