Serum antibodies to human herpesvirus 7, human herpesvirus 6 and cytomegalovirus in patients with idiopathic facial nerve palsy or sudden deafness.

The aetiology of idiopathic facial nerve palsy (Bell's palsy) and sudden deafness are not known, although viruses have been suspected as a cause of them. We investigated the relationship between Bell's palsy or sudden deafness, and reactivation of cytomegalovirus, human herpesvirus 6 (HHV-6) and 7 (HHV-7). Paired sera were collected from 22 patients with Bell's palsy and 24 patients with sudden deafness. IgG antibody titres to HHV-7 were increased in one patient with Bell's palsy. IgG antibody titres to HHV-6 were increased in one patient with Bell's palsy and two with sudden deafness. IgG antibody titres to cytomegalovirus were increased in one patient with sudden deafness. Titres of the three viral antibodies were not increased simultaneously in any patients. These viruses may contribute to the development of Bell's palsy or sudden deafness in some cases. It is, however, unlikely that these viruses are the main cause of Bell's palsy and sudden deafness in the majority of patients.