Irritation from cold wind and water exposure causes the bone surrounding the ear canal to develop lumps of new bony growth which constrict the ear canal. Where the ear canal is actually blocked by this condition, water and wax can become trapped and give rise to infection. The condition is so named due to its prevalence among cold water surfers. Warm water surfers are also at risk for exostosis due to the evaporative cooling caused by wind and the presence of water in the ear canal.