Exostoses of the Outer Ear Canal - Surfer's Ear
Exostoses are bony growths in the medial part of the external ear canal. They are benign and aren't true neoplasms (unlike osteomas). Instead, they are overgrowths of compact bone caused by stimulation by cold water. The more exposed a person is to cold water the more likely exostoses will develop.
The diagram below shows a normal canal on the left and a canal with bony exostoses on the right.
Generally, exostoses are asymptomatic and they slowly enlarge without having any impact until they become very large. They are bilateral but patients often have exostoses on one side that are bigger than those on the other. The side most affected will be the side that most often faces the prevailing wind while out in the sea. The combination of cold water and chilling by wind is important here.
Once above a critical size they cause trapping of water in the ear after swimming or showering, recurring infection in the ear canal, and predispose to wax impaction.
Most patients have three exostoses on each side: a posteriorly based one, an anterior one and a superior one (usually the smallest of the three). They are covered in thin skin.
The eardrum can usually be seen past the exostoses but the view may be very restricted as is shown in the picture below. This is a right ear canal and only a small part of the eardrum can be seen between the exostoses.
The majority of patients do not need management as they are asymptomatic. They are advised to wear ear plugs when in the water and to use swimming caps. Neither of these is popular with surfer's but it is the only practical way of slowing down the growth of bone.
Once large and symptomatic the exostoses should be removed. This is achieved under general anaesthetic by elevating the skin over the exostoses and then removing the bone with an osteotome, drill or piezoelectric saw.
Once removed and the drum is visible once again the skin is replaced and over a period of a few weeks it heals and the patient is symptom free.