Cough: Types, Causes, and Modern Treatment Approaches

Introduction: What is a cough and why does it occur?

A cough is a natural protective reflex of the body aimed at clearing the airways of irritants such as mucus, dust, germs, or foreign particles. Although a cough is often associated with a cold, it can be a symptom of many other conditions, ranging from mild allergies to serious chronic diseases. Understanding the types of cough and its causes is the key to effective diagnosis and treatment.

Types of Cough: Dry and Wet, Acute and Chronic

A cough is classified according to several parameters, which helps doctors determine its potential cause:

• Dry cough: Characterized by the absence of phlegm. It is often irritating, persistent, and can cause a sore throat. Usually associated with viral infections in the early stages, allergies, or airway irritation.
• Wet (productive) cough: Accompanied by the production of phlegm (mucus). Indicates the presence of excess mucus in the airways that the body is trying to expel. Commonly seen in bacterial infections, bronchitis, pneumonia, or chronic lung diseases.

By duration, a cough is divided into:

• Acute cough: Lasts less than 3 weeks. Most commonly caused by respiratory infections (ARVI, influenza).
• Subacute cough: Lasts from 3 to 8 weeks. May be a residual phenomenon after an acute infection.
• Chronic cough: Lasts more than 8 weeks. Requires a thorough examination to identify the underlying cause, which may be related to chronic diseases or external factors.

Common Causes of Cough

The causes of a cough can be diverse and affect both the respiratory system and other organs:

Infectious diseases

• Viral infections: The most frequent cause of an acute cough. These include colds, influenza, and other respiratory viruses, including SARS-CoV-2, which causes COVID-19. Cough is one of the key symptoms of COVID-19, which can progress to pneumonia [5, 6].
• Bacterial infections: Can cause a wet cough, often with purulent sputum. Examples include bacterial bronchitis and pneumonia. In some cases, severe systemic infections, such as sepsis, can lead to acute lung injury or acute respiratory distress syndrome (ARDS), manifesting as cough and shortness of breath [2].

Chronic inflammatory airway diseases

Many chronic airway conditions are associated with so-called type 2 inflammation, which is a common denominator for a subset of patients with diseases such as asthma, chronic obstructive pulmonary disease (COPD), or bronchiectasis [1].

• Bronchial asthma: A chronic inflammatory airway disease often manifesting as a dry cough, especially at night or during physical exertion. In patients with asthma and other allergic conditions, it is important to maintain optimal disease control, even during respiratory virus epidemics [5].
• Chronic obstructive pulmonary disease (COPD): A progressive disease characterized by a chronic cough with phlegm and shortness of breath. Type 2 inflammation may also play a role in some COPD patients [1].
• Bronchiectasis: A condition in which irreversible dilation of the bronchi occurs, leading to a chronic cough with large amounts of sputum and frequent infections. Type 2 inflammation is also observed in a subset of patients with bronchiectasis [1].
• Allergies: Exposure to allergens (pollen, dust, animal dander) can cause a dry, irritating cough.

Diagnosis of Cough: From Symptoms to Molecular Markers

To accurately diagnose the cause of a cough, a doctor conducts a comprehensive examination, which may include:

• History taking and physical examination: Assessment of the nature of the cough (dry/wet, acute/chronic), concomitant symptoms, medical history, and risk factors.
• Laboratory tests: Complete blood count, sputum analysis (to detect bacteria), allergy tests.
• Instrumental studies: Chest X-ray, spirometry (to assess lung function).
• Molecular and cellular endotyping: In the era of personalized medicine, the identification of specific biomarkers is gaining increasing importance. For example, in type 2 inflammation, characteristic of asthma, COPD, and bronchiectasis, blood eosinophil levels, fractional exhaled nitric oxide (FeNO), and immunoglobulin E (IgE) may be elevated. These markers can provide valuable information on disease progression, risk of exacerbations, and treatment response [1].

Modern Approaches to Cough Treatment

Treatment of a cough depends on its underlying cause:

• Symptomatic therapy: Aimed at relieving the cough itself. Antitussives (for a dry cough) or mucolytics and expectorants (for a wet cough) may be used.
• Antibacterial therapy: Antibiotics are prescribed only for a confirmed bacterial infection. For example, in shigellosis, severe forms of salmonellosis, and certain infections caused by Campylobacter sp. [4]. It is important to remember that antibiotics are ineffective against viral infections.
• Anti-inflammatory therapy:
  • Corticosteroids: Widely used to reduce inflammation in asthma and other allergic conditions [5]. In a subset of bronchiectasis patients with type 2 inflammation, corticosteroid therapy may also be effective [1].
  • Biologics: For patients with asthma, COPD, and bronchiectasis who exhibit type 2 inflammation, biologic therapies targeting interleukins IL-4/IL-13, IL-5, and alarmins show promise [1].
• Bronchodilators and antihistamines: Used to dilate the airways and reduce allergic reactions, especially in asthma and allergic cough [5].
• Management of chronic conditions: Patients with chronic diseases (asthma, COPD) must strictly follow the treatment plan developed by their doctor. During epidemics such as COVID-19, telemedicine can be an effective way to maintain contact with the attending physician [5].

When should you see a doctor?

Although a cough often resolves on its own, there are situations when you need to seek immediate medical attention:

• The cough lasts for more than 3 weeks (chronic cough).
• The cough is accompanied by high fever, shortness of breath, or chest pain.
• Appearance of blood in the sputum.
• Cough accompanied by unexplained weight loss.
• Cough in infants or young children accompanied by difficulty breathing.

Sources

1. Type 2 inflammation, the common denominator of chronic airway diseases? (Current opinion in pulmonary medicine, 2025)
2. Infectious diseases in the intensive care unit. (Obstetrics and gynecology clinics of North America, 2003)
3. Review of current and emerging treatments for hand eczema. (Journal of cutaneous medicine and surgery, 2023)
4. Anti-infective treatment of gastrointestinal infections in children. (Infectious diseases now, 2023)
5. Management of pediatric allergies and primary immunodeficiencies during respiratory virus epidemics-the 2020 COVID-19 pandemic: A statement of the EAACI Section on Pediatrics. (Pediatric allergy and immunology : official publication of the European Society of Pediatric Allergy and Immunology, 2020)
6. Daily impact of COVID-19 in gastroenterology. (United European gastroenterology journal, 2020)
7. Rapidly progressive inflammation-mediated coronary artery disease: a case report. (European heart journal. Case reports, 2026)
8. Acute and chronic prostatitis: diagnosis and treatment. (Infectious disease clinics of North America, 1987)

The information presented in this article is for informational purposes only and should not be used for self-diagnosis or self-treatment. Always consult a qualified medical specialist for diagnosis and treatment.