The common causes of hearing loss in one ear in children (mainly sensorineural deafness) are: trauma (head and ear), mumps (viral infection invading cochlear hair cells or nerves), otitis media and otitis media, and congenital developmental problems (congenital underdevelopment of cochlear hair cells or dysplasia). There is no good treatment for long-term sensorineural deafness, but it is recommended to protect the good ear hearing, precautions: usually pay attention to prohibit ototoxic drugs, and then avoid strong noise, as well as reduce the cold to get otitis media.