What Is a Cholesteatoma? 
A cholesteatoma is a skin growth that occurs in an abnormal location, the middle ear behind the eardrum. It is usually due to repeated infection, which causes an ingrowth of the skin of the eardrum. 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 bones of the middle ear. Hearing loss, dizziness, and facial muscle paralysis are rare but can result from continued cholesteatoma growth. 

How Does It Occur?
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 results 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. 

What Are the Symptoms?
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 urgent medical evaluation. 

Is It Dangerous?
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. 

What Treatment Can be Provided?
An examination by an ear nose surgeon can confirm the presence of a cholesteatoma. The extent or growth characteristics of a cholesteatoma will also be evaluated. 

With rare exceptions, cholesteatomas usually require surgical treatment to protect the patient from serious complications. Hearing and balance tests, CAT scans (3-D x-rays) of the mastoid may be necessary. These tests are performed to determine the hearing level remaining in the ear and the extent of destruction the cholesteatoma has caused. 

Surgery (called Mastoidectomy as it involves extensive bone drilling of the mastoid bone found immediately behind the ear), is performed under general anesthesia in most cases. The primary purpose of the surgery is to remove the cholesteatoma and infection and achieve an infection-free, self-cleansing dry ear. Hearing preservation or restoration is a secondary goal of surgery. In cases of severe ear destruction, restoration of normal hearing  may not be possible. Facial nerve repair or procedures to control dizziness are rarely required. Reconstruction of the middle ear to its normal anatomy is usually not possible in one operation; and therefore, a second operation (if deemed necessary) may be performed later. 

Follow-up office visits after surgical treatment are necessary and important, because cholesteatoma sometimes recurs. In cases where an open mastoidectomy cavity has been created, office visits every few months are needed in order to clean out the mastoid cavity and prevent new infections. In some patients, there must be lifelong periodic ear examinations. 

Summary
Cholesteatoma is a serious but treatable ear condition which can only be diagnosed by medical examination. Persisting earache, ear drainage, ear pressure, hearing loss, dizziness, or facial muscle weakness signals the need for urgent evaluation by an Ear Nose Throat Surgeon.