First, we need to know that acute bronchitis refers to the acute inflammation of the bronchial mucosa caused by biological, physical, chemical stimulation, or allergens. The main symptoms in most patients are cough and expectoration. The cough usually presents as a dry cough or a small amount of viscous sputum. Over time, the amount of sputum may increase, or the cough may worsen. A small proportion of patients may have bloody sputum. The cough and expectoration can last for two to three weeks, and in very rare cases, some patients may develop chronic bronchitis if the condition does not resolve. However, for most patients, the primary manifestations are still localized, that is, symptoms like cough and sputum. Systemic symptoms, such as fever, generally present mildly.