Ramsay Hunt syndrome is caused by:

(b) H. zoster(Ref. Cummings, 6th ed., 2622)Herpes Zoster of external ear with facial palsy is known as Ramsay Hunt syndrome.H. simplex is being reported to be associated with Bell's palsy.Facial nerve palsy can also be caused by other viruses, for example HIV, influenza, polio, EBV, etc.