The differential diagnosis for facial paralysis can be separated into infectious and noninfectious. Infectious causes include bacterial (eg, tuberculosis, tetanus, otitis media, meningitis, brain stem encephalitis, Lyme disease, mycoplasma, syphilis, Hansen disease [leprosy], mastoiditis), fungal (eg, cryptococcal), and viral (eg, herpes simplex virus type 1 and type 2, varicella zoster virus, influenza, polio, human immunodeficiency virus, Epstein-Barr virus [ie, mononucleosis], cytomegalovirus, Guillain-Barré syndrome) diseases.
3-5 Noninfectious causes include stroke, pre-eclampsia, trauma, lymphoma, Melkersson-Rosenthal syndrome, Möbius syndrome, tumor, myasthenia gravis, diabetes mellitus, vasculitis, sarcoidosis, benign intracranial hypertension, leukemia, idiopathic cranial neuropathy, and adverse reaction to medication.
4,5 Diagnostic blood work should include a complete blood cell count, fluorescent treponemal antibody test, human immunodeficiency virus test, fasting glucose level, erythrocyte sedimentation rate, Lyme titer, and antinuclear antibody level. A lumbar puncture can be performed to evaluate cell counts, as well as bacterial or viral content.