If the hoarseness has not improved for a month, you need to find out the cause, which can be divided into physiological and pathological factors, and the pathological causes include infectious diseases and neurological diseases. 1. Physiological: boys in the period of voice change will produce hoarse voice symptoms, which is a normal physiological phenomenon, after the period of voice change can return to normal, at this time you should avoid excessive and poor voice. 2. Pathological: If you suffer from infectious diseases, such as upper respiratory tract infections, measles, diphtheria, laryngitis, laryngeal tuberculosis, and scarlet fever, etc., you will have hoarseness due to edema and pain in the throat. In addition, neurological disorders such as paralysis of the superior laryngeal nerve, paralysis of the recurrent laryngeal nerve, and paralysis of the arytenoid muscle can also cause hoarseness due to the narrowing and relaxation of the muscles of the pharynx. If hoarseness is suspected to be pathologic, it is recommended to go to the hospital.