Bell's palsy and herpes simplex virus.

The possible association of some viral infections with the onset of Bell's palsy was examined in a study of 142 patients. The number of probable recent viral infections, as judged by increase in antibody titers or presence of IgM antibodies, did not differ statistically from that found in a sex- and age-matched control group. However, a higher prevalence of herpes simplex virus (HSV) antibodies was found in the patient group with both a complement-fixation (CF) test and a radioimmunoassay (RIA). Moreover, titers of HSV CF antibodies and antibodies against HSV envelope antigens (RIA) were higher in the patient group. The possibility of reactivated HSV infection and transient demyelination of the facial nerve being causatively associated with Bell's palsy is discussed.