About Chronic Cough and Phlegm
"My cold is gone, but the cough persists," "My cough gets worse at night," "I have phlegm that I can't clear" - do you experience any of these problems? The causes of a persistent cough are diverse, including not only post-cold coughs but also asthma, cough variant asthma, COPD, postnasal drip, GERD, pneumonia, and tuberculosis.
At our clinic, we meticulously investigate the cause through medical interviews, auscultation, blood tests, and chest X-rays, and provide treatment tailored to your symptoms.
Causes of cough vary by duration
Coughs are classified by duration into acute cough (less than 3 weeks), subacute cough (3-8 weeks), and chronic cough (more than 8 weeks). The longer the duration, the higher the proportion of non-infectious causes (asthma, GERD, drug-induced).
Main Causes by Cough Duration
Acute Cough (Less than 3 weeks)
| Condition | Characteristics |
|---|---|
| Common cold/Upper respiratory infection | Accompanied by runny nose, sore throat, low-grade fever; resolves in 1-2 weeks |
| Influenza | Sudden high fever, general malaise |
| COVID-19 | Fever, sore throat, loss of taste |
| Acute bronchitis | Cough, phlegm, mild fever |
| Acute sinusitis | Yellow-green nasal discharge, cheek pain, postnasal drip |
| Pneumonia | Fever, difficulty breathing, chest pain, yellow-green phlegm |
| Asthma exacerbation | Wheezing (high-pitched whistling sound), difficulty breathing |
Subacute and Chronic Cough (More than 3 weeks)
| Condition | Characteristics |
|---|---|
| Cough variant asthma | Persistent cough after a cold, no wheezing, responds to bronchodilators |
| Atopic cough | Dry cough, responds to antihistamines |
| Bronchial asthma | Wheezing, nighttime/early morning cough, worsens with allergens |
| Postnasal drip syndrome | Discharge from allergic rhinitis/sinusitis |
| Gastroesophageal reflux disease (GERD) | Heartburn, belching, cough after meals/at bedtime |
| COPD (Chronic Obstructive Pulmonary Disease) | History of smoking, shortness of breath during exertion, phlegm |
| Pulmonary tuberculosis | Cough lasting more than 2 weeks, low-grade fever, weight loss |
| Bronchiectasis | Large amounts of phlegm, recurrent infections |
| Drug-induced cough | Side effect of ACE inhibitors (antihypertensive drugs) |
| Heart failure (cardiac asthma) | Worsens at night, lower limb edema, shortness of breath during exertion |
| Lung cancer | Bloody sputum, weight loss, history of smoking |
| Interstitial pneumonia | Dry cough, shortness of breath during exertion |
Narrowing Down the Cause by Cough Characteristics
| Cough Characteristic | Suspected Condition |
|---|---|
| Dry cough (no phlegm) | Cough variant asthma, atopic cough, interstitial pneumonia, drug-induced |
| Wet cough (with phlegm) | Bronchitis, COPD, bronchiectasis, pneumonia |
| Worsens at night/early morning | Asthma, postnasal drip, heart failure, GERD |
| Worsens after meals/at bedtime | GERD (gastroesophageal reflux) |
| Worsens with cold air/exercise | Asthma, cough variant asthma |
| Lasts more than 2 weeks + low-grade fever | Consider tuberculosis |
| Accompanied by bloody sputum | Lung cancer, tuberculosis, bronchiectasis (requires detailed examination) |
| Yellow-green phlegm | Bacterial infection (bronchitis, pneumonia, sinusitis) |
Signs of Cough Requiring Immediate Medical Attention
If you have any of the following symptoms, please seek medical attention promptly.
There is a possibility of serious conditions such as pneumonia, asthma exacerbation, pulmonary embolism, lung cancer, or tuberculosis.
- Accompanied by high fever (38.5℃ or higher)
- Difficulty breathing or shortness of breath
- Accompanied by chest pain
- Bloody sputum
- Cough lasting more than 2 weeks + low-grade fever/weight loss (suspected tuberculosis)
- Wheezing (high-pitched whistling sound)
- Unable to sleep due to nighttime cough
- Confused consciousness or purple lips
- Rapidly worsening cough
- Cough after international travel
About Cough Variant Asthma
Cough variant asthma is bronchial asthma without wheezing and is one of the most common causes of persistent cough in Japan. Approximately 30% of cases transition to classic asthma within a few years, making early diagnosis and treatment crucial.
Characteristics of Cough Variant Asthma
- Dry cough lasting more than 8 weeks
- Worsens after a cold, exercise, cold air, cigarette smoke, etc.
- More severe at night/early morning
- No wheezing (high-pitched whistling sound)
- Many patients have an allergic constitution (hay fever, atopy, etc.)
- Relief of cough with bronchodilators is a key diagnostic factor
Treatment
- Inhaled corticosteroids: Mainstay of treatment (e.g., Relvar, Anoro Ellipta, Flutiform)
- Bronchodilators: Fast-acting rescue treatment (salbutamol, procaterol)
- Leukotriene receptor antagonists (montelukast): Oral medication
- Usually 3 months or more of continuous treatment
- Relapse is common if discontinued on your own
About Bronchial Asthma
Bronchial asthma is a disease caused by chronic inflammation of the airways, characterized by paroxysmal wheezing, difficulty breathing, and coughing. The number of patients in Japan is said to be about 8 million.
Symptoms of Asthma
- Wheezing (high-pitched whistling sound)
- Paroxysmal difficulty breathing
- Cough and phlegm
- Worsening at night/early morning
- Triggered by exercise, cold air, allergens, infection, stress
Goals of Asthma Control
- No daytime symptoms
- No nighttime awakenings due to symptoms
- No use of rescue medication
- No exercise limitations
- Normal respiratory function
Treatment
| Category | Representative Drugs |
|---|---|
| Inhaled corticosteroids (ICS) | Flutiform, Relvar, Anoro Ellipta, Advair |
| Long-acting β2-agonists (LABA) | Salmeterol, formoterol (ICS/LABA combinations are common) |
| Long-acting anticholinergics (LAMA) | Tiotropium (severe cases) |
| Leukotriene receptor antagonists | Montelukast, pranlukast |
| Rescue bronchodilators (SABA) | Salbutamol (e.g., Meptin) |
| Biologics | Omalizumab, mepolizumab, dupilumab (severe/refractory cases) |
COPD (Chronic Obstructive Pulmonary Disease)
COPD is a progressive disease where the lungs are chronically damaged by smoking, etc., leading to shortness of breath and chronic cough and phlegm. The number of patients in Japan is estimated to be over 5 million, but only a portion receive treatment.
Characteristics
- Many patients are over 40 with a history of smoking
- Shortness of breath during exertion (stairs, uphill)
- Chronic cough and phlegm
- Gradual progression
- Progression cannot be stopped without quitting smoking
Treatment
- Smoking cessation is most important (the only way to slow progression)
- LAMA/LABA inhalers
- ICS (for cases with strong airway inflammation)
- Pulmonary rehabilitation
- Flu and pneumococcal vaccines
- Home oxygen therapy (HOT) for advanced cases
Postnasal Drip Syndrome / Sinusitis
When nasal discharge flows from the back of the nose into the throat (postnasal drip), it causes a sensation of throat discomfort and chronic cough. This is a surprisingly common cause of persistent cough.
Symptoms
- Sensation of phlegm in the throat
- Phlegm and cough upon waking in the morning
- Frequent throat clearing
- Runny nose, nasal congestion
- Yellow-green nasal discharge (bacterial sinusitis)
Treatment
- Antihistamines (allergic)
- Nasal corticosteroids
- Nasal irrigation
- Antibiotics (bacterial sinusitis - low-dose long-term macrolides)
- Referral to ENT for chronic cases
Cough due to Gastroesophageal Reflux Disease (GERD)
Refluxed stomach acid irritates the esophagus and airways, causing a chronic cough. A characteristic feature is a cough that worsens after meals and at bedtime.
Symptoms
- Cough after meals or lying down
- Heartburn, chest discomfort
- Belching, sour liquid rising
- Sensation of a lump in the throat
- Hoarseness
Treatment
- PPIs (proton pump inhibitors): e.g., Takecab, Nexium
- Lifestyle guidance (don't lie down for 2 hours after eating, elevate upper body, avoid overeating)
- Weight loss (for obese individuals)
Possibility of Tuberculosis
Cough lasting more than 2 weeks + low-grade fever/weight loss suggests tuberculosis
Japan is a country with an intermediate incidence of tuberculosis, with approximately 10,000 new patients annually. Elderly individuals, immunocompromised individuals, and those with a history of international travel need to be particularly cautious. Early diagnosis can prevent further spread of infection.
Symptoms Suggesting Tuberculosis
- Cough lasting more than 2 weeks
- Phlegm (sometimes bloody sputum)
- Low-grade fever (around 37℃), night sweats
- Weight loss, loss of appetite
- Severe fatigue
- Family members or close contacts with tuberculosis
- Immunosuppressed state (steroids, anticancer drugs)
Tests and Diagnosis
If chest X-rays show lung shadows, sputum examination and T-SPOT testing are performed. If tuberculosis is confirmed, it will be reported to the public health center and referred to a specialized tuberculosis medical institution.
Examination and Tests
Key Points for Medical Interview
- Duration, onset, and course of cough
- Nature of cough (dry or wet)
- Color, amount, and character of phlegm (presence of bloody sputum)
- Times of worsening (night, early morning, after meals)
- Triggering factors (cold air, exercise, allergens)
- Smoking history, family smoking
- Past medical history (allergies, asthma, COPD, heart disease)
- Medications being taken (ACE inhibitors, etc.)
- History of international travel, contact with tuberculosis patients
Tests Available at Our Clinic
| Test | Purpose |
|---|---|
| Auscultation | Evaluation of wheezing and adventitious breath sounds |
| SpO₂ measurement | Evaluation of oxygenation |
| Chest X-ray | Exclusion of pneumonia, pulmonary tuberculosis, lung cancer |
| Blood tests (CBC, CRP, IgE, eosinophils) | Evaluation of infection and allergy |
| Rapid influenza/COVID-19 test | Acute upper respiratory infection |
| Allergy testing (View39, etc.) | Background evaluation for asthma and atopic cough |
| Peak flow measurement | Objective evaluation of airway narrowing |
Cases Requiring Referral
- Spirometry (pulmonary function test), bronchodilator reversibility test
- Chest CT, bronchoscopy
- Sputum bacterial culture, acid-fast bacilli stain
- T-SPOT test (tuberculosis)
- Management of severe asthma, COPD, interstitial pneumonia
- Suspected lung cancer, detailed investigation of bloody sputum
Fundamentals of Treatment
Acute Cough (Post-Cold)
- Antitussives (dextromethorphan, codeine)
- Expectorants (carbocysteine, ambroxol)
- Antihistamines
- Antibiotics are not needed for viral infections
- Antibiotics for bacterial bronchitis/pneumonia
Treatment for Persistent Cough
| Cause | Main Treatment |
|---|---|
| Cough variant asthma | Inhaled corticosteroids + bronchodilators |
| Atopic cough | Antihistamines |
| Postnasal drip | Antihistamines, nasal corticosteroids, nasal irrigation |
| GERD | PPIs, lifestyle guidance |
| Bronchial asthma | ICS/LABA combination, rescue treatment |
| COPD | LAMA/LABA, smoking cessation |
| Drug-induced (ACE inhibitors) | Discontinuation of causative drug |
Herbal Medicines (Kampo)
| Prescription Name | Suitable Cough |
|---|---|
| Bakumondo-to | Dry cough, dry throat sensation |
| Shoseiryu-to | Watery phlegm, allergic |
| Saiboku-to | Stress-related cough, sensation of lump in throat |
| Hangekoboku-to | Throat discomfort |
| Makyo-kanseki-to | Cough + wheezing (heat pattern) |
Self-Care
Symptom Relief
- Drink plenty of fluids (promotes phlegm expulsion)
- Humidification (50-60% humidity)
- Wear a mask for moisture retention + droplet prevention
- Elevate upper body when sleeping (effective for GERD, postnasal drip)
- Soothe throat with lozenges/honey
- Quit smoking (major aggravating factor for cough)
- Avoid secondhand smoke
Environment
- Air purifier (HEPA filter)
- Clean bedding and curtains (dust mite control)
- Manage pets, mold, and dust
- Avoid inhaling cold air directly
Vaccinations
- Influenza vaccine (annually)
- Pneumococcal vaccine (ages 65+, chronic respiratory disease)
- COVID-19 vaccine
- Pertussis-containing vaccine (booster recommended for adults)
Features of Cough Treatment at Our Clinic
- Chest X-ray to rule out pneumonia, tuberculosis, and lung cancer
- Immediate evaluation with blood tests (inflammation, allergies, eosinophils)
- Rapid influenza, COVID-19, and strep throat tests
- Inhaled steroid and combination therapy for cough variant asthma and bronchial asthma
- COPD treatment and smoking cessation counseling
- Comprehensive approach considering postnasal drip and GERD
- Review of drug-induced cough (ACE inhibitors)
- Individualized treatment incorporating herbal medicines (Kampo)
- Prompt referral to specialized medical institutions for suspected tuberculosis, severe asthma, or suspected lung cancer
- No appointment necessary, walk-ins welcome / Open daily 9:00-21:00 / 1 minute walk from Jujo Station
Don't dismiss it as "just a cough"; start by understanding the cause.
The treatment for persistent cough varies greatly depending on the cause. Continuously taking over-the-counter cough suppressants may not address the underlying cause and can lead to chronic conditions. The first step to treatment is to get an examination and understand the type of your cough.
