A 45-YEAR-old male surfer presents with ear pain. On questioning, the patient says he has been a long-time sea swimmer and surfer. The patient complains that for the past few years, when he gets water in his ears, he has difficulty getting rid of the water. On examination, you note multiple, variably sized skincovered masses in the ear canal. You are unable to see the tympanic membrane. You suspect a diagnosis of ear exostosis (also known as ‘surfer’s ear’) with a mild secondary otitis externa.
External ear exostosis is a hyperostotic outgrowth of the bony ear canal, histologically comprised of broad-based lamellar bone. These lesions tend to occur in swimmers, surfers and scuba divers, and it is thought cold water may cause inflammation and increased vascularity, producing the bone growth. With ongoing cold-water stimulation, the disease process may progress, initially causing water trapping. With consistent water trapping and subsequent hydration of ear canal skin, otitis externa becomes more common. Finally, with end-stage disease, complete external ear canal occlusion occurs, with subsequent maximal (up to 60dB) conductive hearing loss. Osteomas of the ear differ from exostoses because they are usually unilateral and along suture lines, often obscuring a view of the attic of the ear.
The diagnosis is made on otoscopic inspection and occasionally requires very gentle palpation with a blunt-tipped wax curette to exclude soft tissue masses. The bony growths are typically multiple, medial in the external canal and are usually covered by the thin skin of the medial external auditory canal. Exostoses are graded into mild, moderate and severe, depending on the degree of external occlusion. When lesions are lateral, covered in the thicker lateral (glandular) skin of the external auditory canal, or where doubt exists about the diagnosis, palpation of the mass can be performed. The patient should be warned about the manipulation, and under direct vision (with a bright light) a blunttipped wax curette may be used very gently to palpate. Bony growths are rock hard. The clinician should suspect more sinister lesions if the mass is either soft or firm. After visual inspection, clinical testing of hearing is performed including free field and tuning fork tests. If the tympanic membrane can be visualised, then hearing is usually normal. If the patient is complaining of hearing loss and the tympanic membrane can be seen, if there is complete occlusion or the tuning forks are suggestive of a hearing loss, then an audiogram should be organised prior to referral.
With exostoses being a common diagnosis along the Australian coast, the presence of dual pathology (such as otosclerosis, a relatively common cause of conductive hearing loss in the young) should be considered.