Exostosis of the external ear canal, or surfer's ear, is characterized by bony growths within the external auditory canal that most often grow in response to prolonged or frequent exposure to cold water. These can be various shapes and sizes, and are usually multiple and bilateral.

Exostoses occur when cold water comes in contact with the ear canal, causing periostosis. The growths are composed of parallel layers of bone, perhaps because the periosteum stimulates ossification upon each exposure to cold water.

It most often occurs in those who participate in water sports in cold climates, such as surfers, swimmers, or divers.

Symptoms:

• Usually asymptomatic and pain free.
• Large lesions can cause hearing loss, wax / debris buildup, and possibly infection.

Signs:

• Upon examination with otoscope, small bony protrusions can be seen, possibly obscuring visualization of the tympanic membrane.