Cold water swimming, paddleboarding and surfing are all popular pastimes – with millions of people in regularly participating in at least one type of outdoor watersport each year.

But those bravely breaking the waves may not realise they could actually be putting themselves at risk of hearing loss due to external auditory canal exostosis – better known as surfer’s ear.

Surfer’s ear affects the auditory canal – the thin tube which conveys sound waves from our surroundings, channelling them towards the sensory organs which generate our sense of hearing.

These inner portions of the ear are shielded by bone. This is because the anatomical structures that turn air pressure waves into sounds – the eardrum, ossicles and cochlea – are very small, very sensitive and would be easily and irreparably damaged if not protected.

Ideally, our ear canals should be clear and unobstructed. Sure, sometimes they can get clogged up with wax and even sometimes foreign bodies can work their way inside (such as peas, plasticine or even bugs).

But surfer’s ear causes an obstruction of the ear canal in a different manner. Growths start to develop on the bone which lines the auditory canal.

As these growths continue to develop, they push into the canal – effectively narrowing the space inside. In doing so, this can prevent the conduction of sound waves getting through to the eardrum. One symptom patients with surfer’s ear may notice as a result is hearing loss.

Other associated problems may arise, too. The ear canal produces wax. Any narrowing of the canal will more easily retain wax, but also water – not just from swimming, but from wet weather or taking a shower. An accumulation of both in the canal can worsen hearing loss and raise the risk of developing an ear infection.

But what causes surfer’s ear in the first place?

The cause appears to lie in repeated exposure to cold water and high winds – which most surfers encounter while riding a wave, or tumbling off one. It appears to be a problem unique to humans, perhaps because of the configuration of their ears.

While researchers aren’t entirely sure why cold exposure causes the bone to grow abnormally, it’s possible that the ear’s natural response to prolonged cold (which irritates the eardrum) is to create a bigger shield for it. Cold water and wind may stimulate bone cells called osteoblasts, causing new bone to grow – offering more protection.

It’s important to note that surfer’s ear is different from swimmer’s ear – a condition which you may be more familiar with. Though both can arise from water immersion.

Swimmer’s ear, also called otitis externa, is a form of ear infection. It typically results in pain and discharge, and can arise from water accumulating in the ear canal, which then acts as a breeding ground for bacteria. Narrowing of the ear canal can worsen the problem, so swimmer’s ear can also be associated with surfer’s ear.

Surfer’s ear is distinct from swimmer’s ear, where water accumulates in the ear canal. Photo: Pexels.com

It’s estimated that 3-6 per cent of the general population may have some form of exostosis. But the condition does appear to overwhelmingly affect surfers – with one systematic review finding the condition affected an average of around 68 per cent of surfers.

However, surfer’s ear is not unique to surfers. Any sport that exposes an athlete to cold water and wind might result in the same effect. These include wild or outdoor swimming, windsurfing and kayaking.

There’s also a cultural and geographical difference in prevalence across the globe. It’s estimated that 10 per cent of Australians surf, and potentially raising the risk.

You don’t even have to venture into the water to develop surfer’s ear, either. Some research suggests people living near the coast have an increased risk of developing surfer’s ear as they’re more likely to be exposed to cold winds. Other cases have been observed in patients without a clear cause.

The condition might also be more common in males – though this may be due to a larger proportion of men participating in both the sport and the research.

Preventing surfer’s ear