Hi ScubaJorgen,
I believe they are called "exostoses," and you are correct that cold water can contribute to their formation. Here's an article from Sep '01. It's on surfers, but the implications for divers are obvious:
"VETERAN SURFERS WHO CATCH THE WAVE IN COLD WATERS ARE MORE PRONE TO BUILD-UP OF BONE IN THE EAR CANAL
"Surfer's ear may lead to more severe lesions and permanent ear damage.
Denver, CO -- "Surfer's ear," is a progressive buildup of bone within the ear canal, due to long-term exposure to cold water temperatures. The build-up or bony projections are called "external auditory exostoses;" accordingly, the disorder is also referred to as "diffuse exostosis." The condition is observed in avid surfers along the east and west coasts and is, at times, usually worse in the ear that faces the ocean at the time of "catching the wave." Diffuse exostosis is distinct from osteomas of the external auditory canal, which are usually singular, congenital bony malformations that typically occur at embryonic bony suture lines and do not enlarge with time. Surfer's ear must also be distinguished from "swimmer's ear," which is otherwise known as diffuse external otitis.
How long is too much time in the water? A medical research team from Norfolk, VA, set out to demonstrate the prevalence and severity of external auditory exostoses (EAE) in a population of surfers and to examine the relationship between these lesions and length of time surfed as well as water temperature. They believed that subjects who predominantly surfed in colder waters would demonstrate more frequent and more severe exostoses.
The authors of the study, "Surfer's Ear: External Auditory Exostoses Are More Prevalent in Cold Water Surfers," are David F. Kroon, MD, Craig S. Derkay, MD, Louise Lawson, and Joseph McCook, all from the Eastern Virginia Medical School, Norfolk, VA. Their findings were presented on September 11 at the American Academy of Otolaryngology--Head and Neck Surgery Foundation Annual Meeting/OTO EXPO, being held September 9-12, at the Colorado Convention Center, Denver, CO.
Methodology: The study included the participation of 202 avid surfers (91 percent male, 9 percent female, median age 17 years). EAE were graded based on the extent of external auditory canal patency (exposure or openness). Grades of normal (100 percent patency), mild (66-99 percent patency), and moderate-severe (less than 66 percent patency) were assigned. Otoscopic findings were correlated with data collected via questionnaires detailing surfing habits.
Results: There was a 38 percent overall prevalence of EAE, with 69 percent of lesions graded as mild and 31 percent graded as moderate-severe. Professional surfers and those subjects who surfed predominantly in colder waters were found to be at significantly increased risk for the development of EAE. The number of years surfed was also found to be significant, increasing one's risk for developing an exostosis by 12 percent per year and for developing more severe lesions by 10 percent per year. A significant relationship between cold water surfing and more severe EAE was not observed.
Conclusions: EAE are more prevalent in cold water surfers, and additional years surfing not only increase one's risk for developing an EAE, but also for developing more severe lesions."
Best regards.
DocVikingo
