Croup is a special form of dry rales, which are pathological breath sounds emitted by the airway through narrowed bronchi. Chronic respiratory tract inflammation, bronchiectasis, emphysema, bronchial asthma, cardiogenic asthma, acute laryngitis, foreign body obstruction or obstruction by malignant tumors may cause croup, and lying flat at night may also affect breathing and aggravate the symptoms. It is necessary to go to the hospital first to do lung CT examination also need to do lung function, blood gas analysis, sputum culture and other tests, need to be based on the patient’s clinical performance, examination results, under the guidance of the doctor with drugs to actively treat.