Bell's palsy and secondary syphilis: CSF spirochetes detected by immunofluorescence.

Although Bell's palsy is usually idiopathic, occasional cases may have an identifiable infectious cause. When facial paralysis results from syphilis, it usually develops during the tertiary meningovascular stage. We report a 30-year-old man with secondary syphilis who developed facial paralysis associated with acute syphilitic meningitis. Spirochetes were identified in the cerebrospinal fluid by immunofluorescence using standard reagents from the fluorescent treponemal antibody absorption (FTA-ABS) test. Patients with Bell's palsy should be screened for syphilis with a blood FTA-ABS test, and treatment with corticosteroids should be considered only after an infectious cause has been excluded.