The facial nerve runs right through the temporal bone, which is the bone that houses the organs of balance, hearing, and the chain of tiny ear bones (ossicles) that transmit sound from the eardrum to the inner ear. Sometimes when people develop acute ear infections, the inflammation from that infection can transmit to the very nearby facial nerve, and the patient can transiently experience facial weakness. When this happens during an episode of acute otitis media (the common middle ear infections that occur mostly in young children), the data suggest that if the eardrum is opened and the pus is evacuated from the middle ear, facial function will return to normal very quickly, within days to weeks. When people have other forms of ear infection, such as chronic otitis media (a condition where there is long-term infection, and sometimes skin trapped in the middle ear that turns into cholesteatoma), the infection itself can become erosive, almost acting like a tumor, and can cause much more serious and permanent damage to the facial nerve. Thus, if a patient has chronic otitis media and develops facial weakness, we consider it a surgical emergency, whereas if a patient just has an acute ear infection, it can be handled with antibiotics and sometimes an office procedure.
Another kind of ear infection can occur in the bone around the ear canal. It is a serious condition that usually occurs in people with diabetes or who are very immunocompromised, it is called necrotizing otitis externa. This is an erosive and aggressive infection that can sometimes lead to involvement with the facial nerve, and likewise can seriously damage the nerve. Thus, when people have signs of this serious ear canal infection, such as a very deep boring ear pain that is relentless and unresponsive to oral antibiotics, and they have diabetes or other reasons to be immunosuppressed, we investigate carefully for the condition of necrotizing otitis externa so it can be aggressively treated before it affects the facial nerve. If it does affect the facial nerve, surgery is usually required.