Rough breath sounds are abnormal breath sounds caused by mild edema or inflammatory infiltration of the bronchial mucosa resulting in an unsmooth or narrowed wall, resulting in poor airflow entry. It is seen in the early stage of bronchial and pulmonary inflammation. Differential diagnosis: The following symptoms need to be distinguished from each other: diminished breath sounds: breath sounds are mainly alveolar breath sounds, and diminished or absent alveolar breath sounds are associated with reduced air flow in the alveoli or slowed air flow into the lungs and impaired breath sound conduction. They can be localized, unilateral or bilateral. Tubular breath sounds: Tubular breath sounds, also known as abnormal bronchial breath sounds, refer to bronchial breath sounds heard in the distribution area of normal alveolar breath sounds. Low breath sounds: Low breath sounds are most often seen in acute tracheobronchitis, a common condition in which acute inflammation of the tracheobronchial mucosa is caused by a variety of causes. The prognosis is good and the mucosal structure can be completely restored to normal with treatment. The incidence is higher in winter. Signs are mostly absent in the early stages, or scattered dry and wet sounds may be heard at the base of the lungs, and the sounds may disappear after coughing and sputum excretion, and the number of lung sounds may increase during acute attacks, depending on the condition. In patients with chronic bronchitis combined with asthma, extensive croup may be heard during acute attacks with prolonged expiration. Patients with advanced disease often have signs of emphysema due to the complication of emphysema, see the section on obstructive emphysema.