Cough: Causes, Types and Effective Treatment Methods

What Is a Cough and Why Do We Cough?

Hello, I am Dr. Emre Gecer. Coughing is a protective reflex that the body uses to clear mucus, foreign particles, irritants and pathogens from the airways. Known medically as "tussis", cough is one of the most common reasons people see a doctor.

The cough reflex is a highly complex neuromuscular process with three basic phases:

• Inspiratory phase: A deep breath is taken and the lungs fill with air
• Compression phase: The glottis (vocal cords) closes and the expiratory muscles (especially the abdominal and intercostal muscles) contract to raise intra-thoracic pressure — pressures of up to 300 mmHg can be reached
• Expiratory (expulsive) phase: The glottis opens suddenly and air is forced out at very high speed (up to 800 km/h), clearing secretions and particles from the airway

Cough receptors are present at many sites in the respiratory tract: the pharynx, larynx, trachea, main bronchi and even the ear canal (Arnold's nerve reflex). The vagus nerve (cranial nerve X) and the glossopharyngeal nerve (cranial nerve IX) form the afferent limb of the cough reflex. The cough centre in the brainstem evaluates these signals and initiates the cough through efferent (motor) pathways.

Classifying Cough by Duration

Classifying cough by duration is essential for narrowing down its likely causes:

1. Acute Cough (< 3 weeks)

The most common causes:

• Upper respiratory tract infection (URTI / common cold): By far the most common cause. Rhinovirus, coronavirus and parainfluenza are the chief viral agents. Cough is usually accompanied by runny nose, sneezing, mild sore throat and tiredness, and resolves spontaneously in 7–10 days.
• Acute bronchitis: Inflammation of the lower airways — usually viral; more than 90% do not need antibiotics
• Pneumonia: Fever, sputum production, chest pain and shortness of breath may accompany it
• Acute sinusitis: Cough due to post-nasal drip
• Allergic rhinitis flare-up
• COPD exacerbation: Acute worsening of pre-existing chronic lung disease
• Asthma attack
• Foreign-body aspiration: Particularly in children with sudden-onset cough — requires urgent assessment
• Pulmonary embolism: Rare but life-threatening — may be accompanied by shortness of breath, chest pain and haemoptysis

2. Subacute Cough (3–8 weeks)

The most common causes:

• Post-infectious cough: Persistence of cough for weeks after a URTI — reflecting the healing of inflamed airway mucosa. The most common cause of subacute cough.
• Bacterial sinusitis
• Whooping cough (pertussis): Bordetella pertussis infection — severe paroxysmal coughing fits that often end in vomiting (emetic cough). Seen in unvaccinated children and in adults whose vaccine immunity has waned.

3. Chronic Cough (> 8 weeks)

Chronic cough requires a substantial diagnostic and management effort for both patient and physician. The most common causes (the "diagnostic triad") are:

• Upper airway cough syndrome (UACS) / post-nasal drip syndrome: Mucus dripping down from the nose or sinuses into the throat stimulates cough receptors in the pharynx and larynx. The most common underlying conditions are allergic rhinitis, vasomotor rhinitis and chronic sinusitis. Typical features include a sensation of dripping in the throat, frequent throat clearing and nasal congestion.
• Asthma and cough-variant asthma: Asthma is the second most common cause of chronic cough. In "cough-variant asthma" there is chronic dry cough without wheezing or shortness of breath — typically worse at night and in the early morning, triggered by cold air and exercise. Spirometry and bronchial provocation testing (methacholine challenge) are valuable diagnostically.
• Gastro-oesophageal reflux disease (GERD): Stomach acid refluxing into the oesophagus, and sometimes the larynx, triggers cough via a vagal reflex. Some patients have no typical reflux symptoms such as heartburn — "silent reflux". The cough is typically worse after meals, when lying down and when talking.

Other Important Causes of Chronic Cough

• ACE inhibitor–associated cough: Antihypertensive drugs such as enalapril, ramipril and perindopril can cause a dry, persistent cough due to bradykinin accumulation. Occurs in 5–20% of patients. May appear weeks to months after starting the drug. Cough resolves in 1–4 weeks after stopping the drug. Switching to an ARB is the standard alternative.
• Chronic bronchitis: Productive cough for at least 3 months a year in 2 consecutive years — most commonly in smokers
• Bronchiectasis: Irreversible widening of the bronchi — large volumes of purulent sputum
• Pulmonary tuberculosis (TB): Cough lasting more than 2 weeks, night sweats, weight loss and haemoptysis — must always be excluded, particularly in endemic areas. Tuberculosis remains an important public-health issue in Turkey.
• Lung cancer: Particularly in smokers, a new-onset or changing chronic cough, haemoptysis, weight loss and chest pain should be evaluated
• Interstitial lung diseases: Conditions such as idiopathic pulmonary fibrosis — dry cough and progressive shortness of breath
• Eosinophilic bronchitis: Resembles asthma but with normal spirometry — increased eosinophils in the sputum; responds to inhaled corticosteroids

Productive (Wet) versus Non-Productive (Dry) Cough

Productive (Wet) Cough

A cough that produces sputum. The colour and consistency of the sputum offer important diagnostic clues:

• Clear/white mucoid sputum: Viral infection, asthma, COPD
• Yellow-green purulent sputum: Suggests bacterial infection (but can also occur in viral infections — colour alone is not an indication for antibiotics)
• Rusty/brown sputum: Pneumococcal pneumonia, tuberculosis
• Pink frothy sputum: Pulmonary oedema (acute heart failure) — emergency
• Bloody sputum (haemoptysis): Tuberculosis, lung cancer, bronchiectasis, pulmonary embolism
• Large amounts of foul-smelling sputum: Lung abscess

Non-Productive (Dry) Cough

A cough with little or no sputum. Common in the early stages of URTIs, in asthma (cough-variant asthma), in GERD, with ACE inhibitor use and in interstitial lung disease. A dry cough is typically irritative and exhausting.

Effective Home Remedies

1. Honey

Honey is one of the natural remedies with the strongest evidence base for cough. The World Health Organization (WHO) and several clinical studies have shown that honey improves nocturnal cough and sleep quality in children, sometimes more effectively than over-the-counter cough syrups. Mechanism: it forms a soothing (demulcent) layer over the mucosa, with antioxidant and mild antimicrobial effects. One or two teaspoons of honey can be taken directly or added to warm water. Warning: never give honey to infants under one year because of the risk of infant botulism.

2. Steam Inhalation

Inhaling warm steam moistens and softens airway secretions and makes them easier to clear. You can lean over a bowl of hot water with a towel over your head and inhale steam for 10–15 minutes. Eucalyptus oil or menthol may be added if desired. Caution: very hot steam can burn the face and airways; in children, the risk of scalding means extra care is needed.

3. Plenty of Fluids

Adequate hydration thins airway mucus and makes it easier to clear. Warm water, linden tea, lemon-honey water, chicken broth and warm soups both rehydrate and soothe the throat. Caffeine and alcohol should be limited because they can dehydrate.

4. Keep the Room Humid

Dry air makes coughing worse. In winter, indoor air dried by heating is particularly irritating to the airway mucosa. Using a room humidifier (40–60% humidity) or hanging a damp towel can help. If a humidifier is not cleaned regularly it can grow mould and bacteria, so pay attention to its hygiene.

5. Elevate the Head

Raising the head by 15–20 cm at night (with an extra pillow or a wedge under the head of the bed) helps reduce night-time cough. This position eases cough from post-nasal drip and from GERD.

6. Avoid Irritants

• Cigarette smoke (active and passive)
• Dust, mould, pet dander
• Strong perfumes and cleaning products
• Cold, dry air (cover your nose and mouth)

Cough Suppressants (Antitussives): When Should They Be Used?

Cough suppressants should only be considered for dry (non-productive) cough and only when the cough seriously interferes with sleep, daily life or recovery. Using a cough suppressant for a productive cough can be harmful, as it allows secretions to accumulate and infection to worsen.

• Dextromethorphan: The most widely used centrally acting cough suppressant, found in many over-the-counter cough syrups. Generally safe in adults but not proven effective in children (especially under 6 years), where it is not recommended due to the risk of side effects.
• Codeine: An opioid cough suppressant. More potent, but dependence potential, respiratory depression and constipation mean it should be used cautiously. Contraindicated under 12 years.
• Expectorants: Agents such as guaifenesin thin mucus and make it easier to clear. May be useful in productive cough.

Important warning: Over-the-counter cough and cold medicines should not be given to children under 6 — they carry a real risk of serious side effects in this age group and their efficacy is unproven. Honey (over one year of age), fluids and nasal aspiration are safer options.

Red Flags: When You Should See a Doctor Urgently

Seek medical attention without delay if any of the following are present:

• Haemoptysis (coughing up blood): Even small amounts need evaluation to rule out serious causes — tuberculosis, lung cancer, pulmonary embolism
• Shortness of breath (dyspnoea): Unable to breathe at rest or with minimal exertion
• Unexplained weight loss: More than 5% of body weight unintentionally lost in 6 months
• Night sweats: Severe enough to soak the bed — think tuberculosis, lymphoma
• High, persistent fever: Above 38.5 °C lasting more than 3 days
• Chest pain: Particularly pleuritic chest pain (worse with breathing)
• Cough lasting more than 2 weeks: Particularly assess for tuberculosis
• Chronic cough lasting more than 8 weeks: Requires systematic diagnostic work-up
• Hoarseness: Voice change lasting more than 3 weeks — laryngeal pathology
• Cough with swallowing difficulty or shortness of breath: Airway obstruction or aspiration

Chest X-ray: When Is It Needed?

A chest X-ray is indicated for cough in the following situations:

• Haemoptysis (blood in sputum)
• Cough of more than 3 weeks with fever
• Chronic cough (> 8 weeks) — first step in the diagnostic work-up
• When shortness of breath is present
• When chest pain is present
• New or changing cough in someone with a smoking history
• Abnormal lung sounds on examination (crackles, rhonchi, reduced breath sounds)
• In immunocompromised patients (chemotherapy, HIV-positive, transplant)
• Alarm symptoms such as weight loss or night sweats

A normal chest X-ray largely rules out serious underlying pathology, but in some situations (small tumours, interstitial disease) a CT scan may be needed.

Cough in Children: What to Watch For

• Croup (laryngotracheobronchitis): Caused by parainfluenza virus — barking cough, inspiratory stridor, worse at night
• Bronchiolitis: Mainly RSV viral — common under 2 years, with wheezing and respiratory distress
• Foreign-body aspiration: Highest risk between ages 1–3 — sudden-onset cough, wheezing, asymmetric breath sounds
• Asthma: Recurrent attacks of cough and wheezing
• Whooping cough: Paroxysmal coughing fits with a whooping inspiratory sound and post-tussive vomiting

In children, a cough lasting more than 4 weeks is considered chronic (in contrast to the 8-week cut-off in adults) and warrants evaluation.

Conclusion

Cough is a vital mechanism our body uses to protect the airways. The vast majority of acute coughs are viral and resolve spontaneously in 1–2 weeks. Simple measures such as honey, plenty of fluids, steam inhalation and rest can provide significant relief during this period. However, when cough lasts more than 2 weeks, when it is accompanied by alarm features such as haemoptysis, weight loss, night sweats or shortness of breath, or when it becomes chronic, professional medical assessment is essential. Rather than using cough suppressants indiscriminately, it is always better to identify the underlying cause and treat it accordingly.

Wishing you good health.
Dr. Emre Gecer

References

• Murray & Nadel's Textbook of Respiratory Medicine, 7th Edition — Chapter: Cough
• Harrison's Principles of Internal Medicine, 22nd Edition — Chapter: Cough and Hemoptysis
• Tintinalli's Emergency Medicine, 9th Edition — Chapter: Respiratory Distress
• Irwin RS, et al. Diagnosis and Management of Cough: CHEST Guideline and Expert Panel Report. Chest, 2018