Chronic bronchitis is also colloquially known as "old chronic bronchitis." From this name, we can tell that patients usually develop the disease slowly with a long duration, lasting for years, even decades. The symptoms, such as coughing and expectoration, can acutely worsen repeatedly. Most patients cough and produce phlegm mostly when indoors, particularly noticeable upon waking in the morning and also possibly at night. The phlegm is typically white, sticky, or serous and foamy; occasionally, it may be blood-streaked. During acute exacerbations of chronic bronchitis or when accompanied by an infection, pus-like yellow phlegm or green bloody sputum may appear. Additionally, a small number of patients may experience wheezing, also known as asthmatic bronchitis.