The causes of acute laryngitis are: infection, overuse of voice, allergic reaction and other causes. 1. Infection: acute laryngitis is a common respiratory tract infectious diseases, viral or bacterial infections, the beginning of the symptoms such as nasal congestion, runny nose, sore throat, etc., and the downward development of the laryngeal mucous membrane can be caused by acute inflammation of the larynx. 2. Excessive use of voice: Speaking loudly or for too long can damage the laryngeal mucosa and cause hoarseness. 3. Allergic reactions: specific foods, gases or drugs can cause edema of the laryngeal mucosa in atopic patients, resulting in acute laryngitis. 4. Other: laryngeal foreign body, neck and throat trauma and inspection instruments can also lead to laryngitis; tobacco and alcohol stimulation, cold, fatigue, resulting in a decline in the body’s resistance; such as inhalation of ammonia, chlorine and other dust or excessive alcohol and tobacco can also induce acute laryngitis. Acute laryngitis is an acute inflammation of the laryngeal mucosa of the larynx, most often appear after a cold, there is discomfort in time to seek medical attention, diagnosis and treatment.