Cough (Latin tussis; synonyms: barking cough; bronchial cough; chronic cough; persistent cough; epidemic cough; cough irritation; spasmodic laryngeal cough; nervous cough; irritable cough; tussis; uncharacteristic moist cough; uncharacteristic dry cough; ICD-10-GM R05: Cough) is the explosive expulsion of air, either voluntary or triggered by a coughing stimulus via the cough reflex. Cough is triggered by an impulsive expiratory movement produced by the respiratory muscles. On the one hand, coughing is a protective mechanism of the body to remove mucus, dust or foreign bodies from the respiratory tract. On the other hand, it can be a symptom of bronchopulmonary diseases (diseases of the respiratory tract) such as the common cold, bronchitis (inflammation of the bronchial mucosa), pertussis (whooping cough) or bronchial asthma, but also of extrapulmonary diseases such as diseases of the heart or stomach. The intake of medications can also trigger cough. The cause of the cough is an acute viral infection in more than 90% of cases. Postviral cough is when the cough begins with a viral infection and lasts > 3 weeks. In acute cough, upper respiratory tract infections and acute bronchitis are the most common causes (60% of all diagnoses). A specific cough is present when there is a clearly identifiable cause. A nonspecific isolated cough is defined as a chronic dry cough without other symptoms and with unremarkable radiographs. Coughs can be classified according to:
- Mucus production – productive cough, i.e., cough with mucus production and nonproductive (dry) cough.
- Cough sound – barking, clearing throat, roaring, etc.
- Coughing act – e.g., staccato cough as a typical symptom of pertussis.
Furthermore, the cough can be distinguished according to its duration:
- Acute cough (duration ≤ 8 weeks).
- Subacute cough (duration 3-8 weeks)
- Chronic cough (duration > 8 weeks)
A recurrent cough is said to occur when there are ≥ 2 episodes per year for 7 to 14 days without accompanying infection. Cough can be a symptom of many diseases (see under “Differential diagnoses”). Note: In chronic cough, no cause or trigger is found in up to 20% of cases. These cases are referred to as chronic idiopathic cough (CIC). Sex ratio: The sensitivity (hypersensitivity) of the cough reflex is more pronounced in girls and women than in boys and men. Frequency peak: The sensitivity of the cough reflex increases during childhood and puberty. It decreases in older age. Reliable data on the prevalence (disease frequency) in Germany are not available. In some European countries and the USA, a prevalence of between 9-33% is described. Chronic cough is reported to affect approximately 1% of children (9% in Eastern Europe) and 10% of the adult population. Cough is the most common reason for visiting a primary care physician’s office, accounting for approximately 8%. Course and prognosis: An acute cough disappears spontaneously (on its own) in most cases, while chronic cough (most common in smokers) can be very persistent. A cold-related cough lasts seven days with or without treatment. In 50% of patients, the cough lasts up to three weeks and in 25% of patients even longer than one month.Adenovirus or mycoplasma infections, the cough can last up to two months, and in pertussis (whooping cough) even longer.In the case of chronic cough (cough > 8 weeks), a visit to the doctor for further diagnostics (X-ray chest, lung function test, etc.) is required to clarify the exact cause. Only in this way is adequate therapy possible. Note: A subacute cough (duration 3 to 8 weeks) improved over time in all studies with and without medication. Conclusion: The natural course of the disease and its self-limiting character (“ending without external influences”) must be explained to the patients as a matter of priority.
