1. Idiopathic |
a. Bell's palsy |
b. Melkersson–Rosenthal syndrome (recurrent alternating facial palsy, furrowed tongue, faciolabial oedema) |
2. Infection |
a. Otitis media |
b. Mastoiditis |
c. Herpes zoster cephalicus (Ramsay–Hunt syndrome) |
d. Chickenpox |
e. Encephalitis |
f. Meningitis |
g. Poliomyelitis (type I) |
h. Mumps |
i. Infectious mononucleosis (glandular fever) |
j. Malaria |
k. Tuberculosis |
l. Lyme disease |
m. HIV |
3. Trauma |
a. Skull base fractures |
b. Facial injuries |
c. Penetrating trauma to middle ear |
d. Barotrauma (altitude paralysis/scuba diving) |
4. Metabolic |
a. Diabetes mellitus |
b. Hypertension |
c. Acute porphyria |
5. Neoplastic |
a. Cholesteatoma |
b. Leukaemia |
c. Haemophilia |
d. Fibrous dysplasia |
e. Parotid tumours |
f. Facial nerve tumour |
g. Cerebello-pontine angle tumours |
6. Toxic |
a. Tetanus |
b. Diphtheria |
c. Thalidomide |
d. Carbon monoxide |
7. Iatrogenic |
a. Postimmunisation |
b. Antitetanus serum |
c. Vaccine for rabies |
d. Parotid surgery |
e. Mastoid surgery |
f. Forceps delivery |
8. Autoimmune syndrome |
a. Thrombotic thrombocytopaenic purpura |
b. Kawasaki disease |
c. Guillian barre/Miller–Fisher syndrome |
9. Neurological |
a. Millard-Gubler syndrome (abducens palsy with contralateral haemiplegia due to lesion in the base of pons involving corticospinal tract) |
b. Opercular syndrome (cortical lesion in facial motor area) |
10. Congenital |
a. Dystrophia myotonica |
b. Moebius syndrome (facial diplegia associated with other cranial nerve deficits) |