Idiopathic facial palsy. Viral, hereditary, or both?

Two cases of acute peripheral facial paralysis occurring in two siblings in a family of six members, who all developed influenza-like symptoms, are reported. Both patients with facial paralysis, as well as two other members of the family had elevated titers against herpes simplex virus, even though it was not possible to demonstrate any raise in titers between the acute and convalescent phase. The "epidemic" occurrence is from a statistical point of view more than just a coincidence, and it is concluded that these findings support the hypothesis that Bell's palsy may be caused by reactivation of herpes simplex virus, probably facilitated by some hereditary component. The authors suggest that a combination of infectious (most likely viral) and hereditary factors may be etiologically important for the occurrence of acute peripheral facial paralysis.