Latent viruses and Bell's palsy in children.

4 children with unilateral facial palsy--Bell's palsy (BP)--had serological evidence of primary infection with Epstein-Barr virus (EBV). Concomitant infection with cytomegalovirus (CMV) was demonstrated in 1 child while in all 4 children a rise in antibody titers to an additional one or two viruses was demonstrated. The viruses involved were herpes simplex, CMV and adenovirus which are latent in humans. Immunosuppression induced by EBV and steroid treatment may cause reactivation of these viruses resulting in rise in antibody titers. The need for prolonged serological follow-up for possible reactivation of latent viruses in BP is emphasized.