Bell's palsy. Ensuring the best possible outcome. Bell's palsy is thought to be an idiopathic polyneuritis and must be distinguished from other disorders that cause facial weakness. In most cases, differentiation can be accomplished on the basis of the history, physical examination, and clinical course. Routine follow-up care ensures that recovery is occurring. Electrodiagnostic testing often helps to assess prognosis. Eye care and corticosteroid therapy are recommended. 