Clinically, there are acute laryngitis and chronic laryngitis. Usually, only acute laryngitis will have the manifestation of dyspnea, especially infants and children are more obvious. Chronic laryngitis, on the other hand, has no obvious dyspnea in most cases. Dyspnea in acute laryngitis is mostly inspiratory, that is, it is obvious during the inspiratory movement, accompanied by obvious inspiratory laryngeal ringing and triple concave sign, which refers to the depression of the suprasternal fossa, the supraclavicular fossa and the intercostal space, and it is due to the obstruction of the vocal folds and the negative pressure of the respiratory tract. In infants and children, due to the relatively small size of the vocal folds and trachea, even mild laryngitis and slight swelling of the mucosa may result in significant dyspnea, most of which is accompanied by a typical barking cough.