If your child has come home from a swim lesson tugging at one ear and wincing, a likely culprit is swimmer’s ear. (The other usual suspect is a middle ear infection, and telling them apart is a job for the doctor.) Swimmer’s ear is common, it’s treatable, and a lot of it is preventable.

So this article spends most of its time there, then covers sore shoulders, breaststroke knee and cramp more briefly.

I keep three things separate: what medical sources say (quoted, with dates), what research measured (with sample sizes and caveats), and my own coaching judgement, which is labelled. I’m a swim coach, not a doctor. Nothing here is a diagnosis, and nowhere will I tell you how to dose anything.

What is swimmer’s ear?

The CDC’s fact sheet Swimming and Ear Infections (9 June 2020) puts it plainly:

“Swimmer’s ear (also known as otitis externa) is a bacterial infection typically caused by water that stayed in the outer ear canal for a long period of time, providing a moist environment for bacteria to grow. Anyone can get swimmer’s ear, but it is most often seen in children. Swimmer’s ear cannot be spread from one person to another.”

So it isn’t contagious: one child in a class getting it doesn’t mean the others will catch it. And the same fact sheet stresses it is “not the same as a middle ear infection, which is common in children.” Swimmer’s ear is in the canal, outside the eardrum, not behind it.

Why Singapore makes it more likely

From HealthHub’s page on otitis externa (contributed by Sengkang General Hospital, last reviewed 1 September 2025):

“Someone who swims frequently is also predisposed to external ear infection. Prolonged exposure to moisture results in the water-resistant coating and skin becoming soft, allowing bacteria to infect the skin. High humidity in tropical countries, like Singapore, ups the risk for external ear infections.”

The StatPearls summary on otitis externa (NCBI Bookshelf) says the same thing from another angle: it’s called swimmer’s ear “as it often occurs during the summer and in tropical climates and having retained water in the ears increases the risk for it.” In Singapore it’s always summer.

HealthHub also names the other half of the problem, which has nothing to do with swimming:

“Trauma to the skin of the ear canal from cotton tips or fingernails can result in a break in the barrier.”

Symptoms of swimmer’s ear

The CDC fact sheet lists:

  • Pain when the outer ear is tugged, or when you press on the tragus (the small flap that sticks out in front of the ear canal)
  • Itchiness inside the ear
  • Drainage from the ear
  • Redness and swelling in the ear

HealthHub adds an itchy or painful ear with “foul-smelling fluid discharge”, hearing that’s affected or ears that feel blocked, and outer ear skin that is “red and swollen, and extremely sensitive to touch”.

That tug test is one parents can notice at home. If it makes your child yelp, mention it to the doctor.

Swimmer’s ear treatment: this one’s for the doctor

The CDC fact sheet says: “Check with your healthcare provider if you have ear pain or drainage from the ear,” and “Swimmer’s ear can be treated with antibiotic ear drops.” HealthHub says it “can be treated by your family doctor with antibiotic ear drops”, that some prescription drops also contain steroids to bring down pain and swelling, and that occasionally an ENT specialist needs to clean the canal.

In Singapore, that means your GP or a polyclinic. Which drops and how many is exactly the bit you need a doctor for.

When to see a doctor sooner rather than later

The NHS page on ear infections (last reviewed 16 January 2025) covers all ear infections, not just swimmer’s ear. It advises an urgent appointment if symptoms come with, among other things: feeling generally unwell or a very high temperature, swelling around the ear, fluid coming out of the ear, a change in hearing, diabetes or a heart, lung, kidney or neurological condition, or a weakened immune system.

That diabetes point matters for some adult learners. HealthHub warns that people with diabetes are at higher risk and more prone to “an aggressive form of infection called malignant otitis externa, in which the infection involves the skull bone.” If you’re diabetic and your ear hurts after swimming, don’t wait it out.

Swimmer’s ear drops: when not to use them

Two different things get called “swimmer’s ear drops”: prescription drops from your doctor, which treat an infection, and ear-drying drops, used after swimming to help prevent one. On drying drops, the CDC fact sheet says to check with your healthcare provider first, and then, in bold:

“DON’T use these drops if you have ear tubes, punctured ear drums, swimmer’s ear, or ear drainage.”

“Ear tubes” are what Singapore parents usually call grommets. If your child has grommets, has a perforated eardrum (or you’re not sure an old one has fully healed), or already has a sore, leaking ear, don’t put over-the-counter drying drops in. Ask the doctor.

No swimming while it’s infected

The NHS list of things not to do with an ear infection includes “do not go swimming while you have an ear infection” and “do not let water or shampoo get in your ear”.

My coaching judgement: I’d much rather your child miss a lesson than swim through an infected ear. One missed week makes no real difference to their progress. Just message me and let me know.

How to prevent swimmer’s ear

This is the part you can actually control. From the CDC fact sheet:

“Keep ears as dry as possible.”

And, under that point:

“Use a bathing cap, ear plugs, or custom-fitted swim molds when swimming.”

“Dry ears thoroughly after swimming or showering.”

The CDC then spells out how: towel the ears dry, tilt the head so each ear faces down, and pull the earlobe in different directions to let water drain out. If water is still in there, it suggests a hair dryer on the lowest heat and fan setting, held several inches from the ear. HealthHub gives the same head-turn and gentle ear-pull advice, and suggests earplugs.

And the one that surprises people:

“DON’T try to remove ear wax. Ear wax helps protect the ear canal from infection.”

The CDC also says not to put anything in the ear canal, cotton buds included. HealthHub allows that “gentle use of cotton tips may be necessary”, but neither source wants you digging. Routinely cotton-budding a child’s ears after every swim to “get the water out” can be the very thing that breaks the skin’s barrier.

My coaching judgement on caps and earplugs: earplugs don’t get in the way of learning to swim, and if your child has had swimmer’s ear before, I’m happy for them to wear them. Keep them clean and well-fitting, though: the NHS lists “wearing earplugs” among the things that can irritate the ear canal, even as it recommends “earplugs or a swimming hat” for swimming. One more caveat: some nervous beginners hate the muffled feeling at first. If that adds to the fear, we focus on drying properly afterwards instead.

Swimmer’s shoulder: probably not your child’s problem

StatPearls describes it as an overuse problem driven by “the high volume of repetitions required during training”. It’s an umbrella term for several different shoulder conditions.

Notice the words high volume. The most relevant review on training volume, a 2020 systematic review in the Journal of Athletic Training (12 studies, 1,460 competitive swimmers), found the young competitive swimmers in those studies (under 15) were training roughly 6.6 to 12.2 hours a week. In their discussion, the authors explain why that group showed less of a problem:

“Young competitive swimmers performed lower volumes of swim training, making them less susceptible to overloading of the soft tissue structures about the shoulder.”

Their formal conclusion is more cautious: “Evidence suggests that swim-training volume was associated with shoulder pain in adolescent competitive swimmers (level II conclusion).” So the risk is real once children become teenagers in squad training.

Studies of the young competitive swimmers “showed no significant results” linking training volume to shoulder pain. But pain wasn’t rare in that group: 20% in one study (85 swimmers training about 7–11 hours a week) and 49% over a year in another (149 swimmers aged 11–15, about 9–12 hours a week). The volume link itself showed up in adolescent, adult and masters swimmers, including one group of 67 masters (adult competitive) swimmers training only about 4–5 hours a week, of whom 19.4% had shoulder pain. The highest pain rate in the review, 91.3%, came from one study of 80 club-to-international swimmers with an average age of about 16, training around 17 hours a week. That number gets quoted a lot. It does not describe your child.

Arguing against my own interest (my coaching judgement): none of these studies looked at children in weekly lessons, so this is inference, not data. But most children doing one 45-minute lesson a week are very unlikely to get swimmer’s shoulder. That’s under an hour, against 6–12 hours for the youngest competitive group in that review. Anyone telling you weekly lessons put your child’s shoulders at risk should show you their numbers.

Where it does start to matter is when a child moves into squad training and the hours jump. The review’s advice there is specific: “Developing athletes should be aware of and avoid a sudden and large increase in swimming volume.” I’ve written more about which strokes load the shoulder most, and why a wide, thumb-first entry is the habit worth fixing early, in the backstroke article. The front crawl article covers the entry and pull too.

For adults: shoulder pain that comes back every swim, or is getting worse, is a reason to see a doctor or physio, not to push through.

Breaststroke knee

Relevant here, because so many Singapore learners, adults especially, swim almost nothing but breaststroke.

A 2025 systematic review of swimming injuries in Applied Sciences (nine studies) found the shoulder was the most frequently affected joint. The knee came second in four of the nine studies, and the abstract ties it to “the biomechanical demands of breaststroke”. Six of the nine studies were of elite swimmers.

What research measured, with the caveats: the classic studies are old and mostly of competitive swimmers.

  • Vizsolyi and colleagues (1987) surveyed 391 athletes and found knee pain in 73% of breaststroke specialists and 48% of non-breaststrokers. Age, years of competitive swimming and training characteristics were linked to more pain.
  • Rovere and Nichols (1985) examined 36 competitive breaststrokers. 86% had had at least one episode of breaststroke knee pain, and more frequent pain went with more breaststroke training distance and less warm-up.
  • Stulberg and colleagues (1980) examined 23 breaststroke swimmers aged 6 to 30 with painful knees. Where the knee hurt depended on how the kick was done, the pain-free swimmers they compared used a consistently different kick, and they recommended treatment focus on correcting the kick.

These are small, old studies, mostly of competitive swimmers. They show breaststroke knee is real and linked to volume and technique. They don’t give a risk number for an adult doing a few lengths at Bishan on a Sunday.

A 2015 review in the Aspetar Sports Medicine Journal explains the mechanism: the kick puts “high valgus loads” on the inside of the knee as it snaps from bent to straight. On management:

“In breaststroke swimmers, a temporary reduction in breaststroke-specific training load will decrease medial knee load. It is often only breaststroke load that needs to be controlled. Swimmers with medial knee pain can usually continue swimming using the other strokes – if pain-free.”

They also note: “You will commonly only improve a breaststroker’s knee pain once you have improved hip function.”

My coaching judgement: if the inside of your knee aches during or after breaststroke, tell me. Often the kick is too wide or too forced, and that’s fixable. It’s also a very good reason to learn a second stroke. That’s a large part of what stroke correction and our adult lessons are for. If the pain persists or the knee locks, catches or swells, that’s for a doctor or physio, not a coach.

Cramp

The NHS page on leg cramps (last reviewed 1 December 2023) isn’t swimming-specific. It says cramps can last “from a few seconds to 10 minutes”, that the calf is the usual spot, and that stretching and massaging the muscle may ease it. Among its listed causes is “putting too much strain on muscles during exercise, which can be worse in hot or humid weather”, along with not drinking enough fluids. The NHS says to see a GP if cramps last longer than 10 minutes, keep disturbing your sleep, or come with numbness or swelling in the legs.

My coaching judgement on cramp in the water: the bigger risk, as I see it, is panicking about the cramp. What I teach is this: don’t fight it, roll onto your back and float, call out or raise an arm, and work your way to the wall. Once you’re holding on, stretch it out. That’s one more reason floating on your back matters so much. Staying up and breathing for 30–60 seconds is one of the core survival skills covered in the water competency article.

Red, stinging eyes

The CDC’s page on eye irritation from pool chemicals (28 May 2025) explains that when chlorine combines with sweat, urine, dirt, skin cells, deodorant and makeup that wash off swimmers, it forms irritants called chloramines. Those cause red, itchy eyes, and they’re what you’re probably smelling when a pool “smells of chlorine”. The CDC’s advice to swimmers: use the toilet and shower before getting in, and never pee in the water.

My coaching judgement: well-fitting goggles sort out most of this, and a strong chemical smell is worth mentioning to pool staff.

The short version

  • Swimmer’s ear is the common one. Keep ears dry, don’t dig at them, and see a GP or polyclinic if there’s pain or discharge.
  • Don’t use drying drops with grommets, a perforated eardrum, or an ear that’s already sore or leaking.
  • Swimmer’s shoulder and breaststroke knee are volume-and-technique problems. A weekly lesson is far below the volumes studied; bad technique is still worth fixing early.
  • Pain that keeps coming back goes to a doctor or physio, not to swimming through it.

If you’d like a stroke checked for something that’s starting to niggle, WhatsApp me on 9677 3858.

Sources