A cholesteatoma is a skin growth that occurs in an abnormal location, usually in the middle ear behind the eardrum. It is most commonly due to repeated infection, which causes an ingrowth of the skin of the eardrum. It may also be congenital (present at birth). Cholesteatomas often take the form of a cyst or pouch that sheds layers of old skin that builds up inside the ear. Over time, the cholesteatoma can increase in size and destroy the surrounding delicate hearing bones of the middle ear (ossicles). Chronic infection and hearing loss are common side effects of the disease process. Meningitis, dizziness, and facial muscle paralysis are rare but can result from continued cholesteatoma growth.
A cholesteatoma usually occurs because of poor eustachian tube function as well as infection in the middle ear. The eustachian tube conveys air from the back of the nose into the middle ear to equalize ear pressure ("clear the ears"). When the eustachian tubes work poorly (perhaps due to allergy, a cold or sinusitis), the air in the middle ear is absorbed by the body, and a partial vacuum forms in the ear. The vacuum pressure sucks in a pouch or sac by stretching the eardrum, especially areas weakened by previous infections. This sac often becomes a cholesteatoma. A rare congenital form of cholesteatoma (one present at birth) can occur in the middle ear and elsewhere, such as in the nearby skull bones. However, the type of cholesteatoma associated with ear infections is most common.
Initially, the ear may drain, sometimes with a foul odor. As the cholesteatoma pouch or sac enlarges, it can cause a full feeling or pressure in the ear, along with hearing loss. (An ache behind or in the ear, especially at night, may cause significant discomfort.) Dizziness, or muscle weakness on one side of the face (the side of the infected ear) can also occur. Any, or all, of these symptoms are good reasons to seek medical evaluation.
Ear cholesteatomas can be dangerous and should never be ignored. Bone erosion can cause the infection to spread into the surrounding areas, including the inner ear and brain. If untreated, deafness, brain abscess, meningitis, and rarely death can occur.
See Cholesteatoma Removal for information on procedures to remove cholesteatomas.