When the facial canal that courses through the middle ear is dehiscent, meaning that the facial nerve is uncovered, a middle ear infection can cause a facial paralysis. Some people are born with a dehiscent facial nerve in the middle ear, and in others the middle ear infection erodes the bony covering of the facial nerve. Cholesteatoma, a growth of skin in the middle ear, may also erode the bony covering of the facial nerve and cause a facial paralysis.