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Wet cough
Last reviewed: 06.07.2025

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Depending on the above reasons, a distinction is made between unproductive (dry) and productive (wet) cough. Wet cough is characterized by the separation of sputum. For some diseases, only unproductive (dry) cough is typical, for others, especially inflammatory diseases of the respiratory system, productive cough usually replaces unproductive cough. In some cases (for example, with acute laryngitis), after the phase of productive cough, a phase of unproductive cough is again noted, which occurs due to a decrease in the sensitivity threshold of cough receptors. In the latter case, the prescription of antitussives rather than expectorants is pathogenetically justified.
A wet cough is characterized by the production of sputum.
- Increased sputum production is typical for inflammation of the bronchi (bacterial or viral infection), inflammatory infiltrate of the lungs (pneumonia).
- Long coughing fits ending with expectoration, often very pronounced before sleep and even more severe in the morning after sleep, are characteristic of chronic bronchitis. Sometimes, with such a coughing fit, loss of consciousness may occur - syncopal condition, cough fainting syndrome.
- Sometimes the discharge of a large amount of sputum occurs at one time, "with a full mouth" (emptying a lung abscess, large and multiple bronchitis), especially in a certain body position.
- Chronic productive (wet) cough is observed in bronchiectasis. In unilateral bronchiectasis, patients prefer to sleep on the affected side to suppress the cough that bothers them. It is in this situation that postural (positional) drainage of the bronchi (increasing the discharge of sputum by giving the patient a position in which it is discharged by gravity) becomes important as a treatment procedure. In addition to a special body position, an extended forced exhalation is necessary, which creates a high-speed air flow that carries away bronchial secretions.
Despite a strong cough impulse, the resulting sputum may not be coughed up. This is usually due to its increased viscosity or voluntary swallowing. Often, a slight cough and a scanty amount of sputum are not considered a sign of illness by the patient (for example, a habitual morning cough with smoker's bronchitis), so the doctor should himself focus the patient's attention on this complaint.
Sputum examination
To establish a diagnosis of a lung disease, it is of great importance to study the properties of the sputum secreted or obtained by special methods (aspiration of the bronchial contents during bronchoscopy).
Properties of sputum
It is necessary to pay attention to the following properties of sputum:
- quantity;
- consistency;
- appearance, color, smell;
- presence of impurities;
- layering;
- data obtained from microscopic (including cytological) examination are also taken into account.
The amount of sputum secreted per day can vary widely, sometimes reaching 1-1.5 liters (for example, in large bronchiectasis, abscesses and tuberculous cavities of the lungs, cardiogenic and toxic pulmonary edema, emptying through the bronchus of the pleural cavity in purulent pleurisy, bronchorrhea, pulmonary adenomatosis).
Sputum in purulent-inflammatory diseases of the lungs can be liquid or viscous depending on the amount of mucus in it. Most often, sputum has a mucopurulent character. Particularly viscous sputum is observed in acute inflammatory diseases of the lungs, in the initial period of an attack of bronchial asthma. Less often, sputum is liquid or serous (predominance of protein transudate), for example, in pulmonary edema, alveolar-cell cancer.
When left to stand, sputum separates into three layers: the upper layer is a foamy serous fluid, the middle layer is liquid, contains many leukocytes, erythrocytes, bacteria (the most significant in volume), the lower layer is purulent (microscopic examination of sputum reveals neutrophils, various types of bacteria). Such three-layer sputum can have an unpleasant (putrid, foul) odor, which is usually characteristic of anaerobic or a combination of anaerobic and streptococcal infections, as well as the decay of lung tissue.
A yellowish-green color of sputum is typical for a bacterial infection. A large number of eosinophils (allergy) sometimes give sputum a yellow color. In severe jaundice, sputum may resemble light bile, and gray or even black sputum is sometimes observed in people who inhale coal dust (miners).
If there is a productive cough, material should be obtained from the trachea and bronchi (not saliva) for subsequent Gram staining and microscopy.
Questions to ask when you have a productive cough
- How often do you cough up phlegm?
- What is the daily amount of sputum produced?
- How difficult is it to cough up phlegm?
- In what body position is it better to cough up phlegm?
- What color is sputum usually?
- Are there any impurities (blood - scarlet or dark, dense particles).