What Are Exostoses of the Ear Canal?

Exostoses of the ear canal are benign bony growths that develop in the external auditory canal, the tube that leads from the outer ear to the eardrum. These growths typically arise as multiple, rounded elevations of dense bone covered by a thin layer of skin. They are often bilateral, meaning they affect both ears, and are most frequently seen in individuals who spend prolonged periods in cold water.

The condition is so strongly associated with cold-water exposure that it is widely referred to as surfer’s ear. However, any activity that subjects the ear canal to cold wind or water, such as open-water swimming, kayaking, paddleboarding, windsurfing, or diving, can lead to the formation of exostoses. The growths develop slowly over years, often taking decades to become noticeable.

How Exostoses Form

The exact mechanism behind the formation of exostoses is not fully understood, but the prevailing theory involves repetitive thermal stimulation. When cold water or cold air enters the ear canal, the local blood vessels constrict in response to the temperature drop. The body attempts to rewarm the area by stimulating new bone growth, potentially as a protective response. Over time, repeated exposure leads to the gradual accumulation of bone.

This process is distinct from the genetic or inflammatory conditions that cause other types of bony growths. Exostoses are considered reactive lesions rather than true tumors. They are distinct from osteomas, which are solitary, pedunculated bone tumors that usually arise from a single site in the ear canal. Exostoses, by contrast, tend to be broad-based and multiple, often appearing in clusters along the floor and walls of the canal.

Symptoms of Exostoses of the Ear Canal

Many people with exostoses of the ear canal have no symptoms at all, especially when the growths are small. As the bony masses enlarge, they narrow the ear canal and can cause a range of problems:

• A feeling of fullness or pressure in the ear
• Recurrent ear infections due to trapped water and debris
• Difficulty hearing, known as conductive hearing loss
• Earwax impaction, as the narrow canal prevents natural self-cleaning
• Chronic discharge or otorrhea if infection develops
• A sensation of water being stuck in the ear after swimming
• Ringing in the ear, known as tinnitus, in some cases

The narrowing of the ear canal is the primary cause of symptoms. In severe cases, the canal may become almost completely obstructed, which can significantly reduce sound transmission to the eardrum. This type of hearing loss is conductive in nature, meaning the inner ear and auditory nerve remain healthy, but sound waves cannot travel effectively through the blocked canal.

Diagnosis

Exostoses of the ear canal are typically diagnosed during a routine ear examination. A healthcare provider using an otoscope can usually see the smooth, pale bony swellings narrowing the ear canal. In cases where the canal is very narrow or filled with wax and debris, the provider may need to clean the ear before a full assessment is possible.

Imaging studies such as a computed tomography scan are generally not required for diagnosis but may be used before surgery to determine the extent of the bony involvement and to plan the procedure. Audiometry, or a hearing test, is often performed to document the degree of hearing loss and to confirm that the hearing loss is conductive rather than sensorineural.

Treatment and Management

For individuals with no symptoms or only minimal narrowing, no treatment is necessary. Management focuses on prevention and keeping the ears healthy. Strategies include:

• Wearing earplugs or swim molds to reduce cold-water exposure
• Using a well-fitting hood or cap for warmth in cold, windy conditions
• Drying the ears thoroughly after swimming or showering
• Using preventive ear drops to help clear trapped water
• Regular professional cleaning to remove wax that cannot escape naturally

When symptoms become significant, such as recurrent infections, progressive hearing loss, or a complete blockage of the ear canal, surgery may be recommended. The surgical removal of exostoses is performed under a microscope, typically through the ear canal itself. The surgeon removes the bony growths and may place skin grafts to cover the exposed bone and encourage proper healing.

Surgery for exostoses of the ear canal is generally highly effective. The procedure restores the normal width of the canal and improves hearing. Recovery involves keeping the ear dry and protected for several weeks, and patients are usually advised to avoid swimming and other water activities during the healing period. As with any surgery, there are potential risks, including infection, damage to the eardrum, changes in taste, and the possibility that the exostoses may gradually recur with continued cold-water exposure.

Prevention and Outlook

The best way to prevent exostoses of the ear canal is to limit the entry of cold water and cold air into the ears. Custom-molded earplugs are particularly effective for regular surfers, divers, and cold-water swimmers. These plugs create a tight seal that keeps the ear canal warm and dry.

For those who already have exostoses, continued prevention is important to slow progression. The condition is not dangerous in itself, but the complications it causes, such as infections and hearing loss, can affect quality of life and require medical attention.

With appropriate management, most people with exostoses of the ear canal maintain good ear health. Even for those who require surgery, the long-term outlook is excellent, and normal hearing is usually restored once the canal is reopened and the ear has healed.