Red eyes after swimming: infection or chlorine?

Every school holiday brings me the same pair of red eyes and the same pair of questions. The child has been in the pool. The eyes came home pink and stinging. Is it the chlorine, and is it catching?

Those two questions have different answers and different consequences, so it is worth being able to tell them apart at home on a Saturday evening. The good news is that they behave differently enough that you usually can.

Her eyes go red every time she swims. Is the chlorine too strong?

Usually the opposite of what you would expect. The thing stinging your daughter's eyes is generally not the chlorine itself. It is what the chlorine turns into once it has met everything the swimmers brought in with them.

Chlorine reacts with sweat, urine, dirt, skin cells, deodorant and make-up, and the products of that reaction are called chloramines. Chloramines are the irritant. They are what make eyes red and itchy, and in a badly ventilated pool they also cause the coughing, the runny nose and the wheeze that some children get on the way home. Children with asthma can find a poorly kept indoor pool sets them off.

So a pool that stings is not usually an over-chlorinated pool. It is more often a pool carrying a heavy load of what people brought into it, which is also why the same child can swim happily in one pool and come out red from another.

Is it the pool, or has he caught something?

Watch three things: which eye, how fast, and what comes out of it. Chloramine irritation affects both eyes at once, starts during or straight after the swim, and produces stinging and redness with watering but nothing sticky. It eases over a few hours and it is much better by bedtime.

Infection usually starts in one eye, arrives hours or a day later rather than in the changing room, and produces discharge. If the eye is sticky, if there is pus, if the lashes are glued together in the morning, that is not the pool water. Conjunctivitis that produces sticky pus is contagious, and so, usually, is an eye that is red and feels gritty.

There is a third pattern worth knowing, because it gets blamed on the pool constantly. An allergic eye is red and watery too, but it is itchy in a way that makes a child dig at it with their knuckles, and it is not contagious. If your child's eyes are itchy well beyond swimming days, the reasons children rub their eyes is the more useful place to start than the pool chemistry.

The pool smells strongly of chlorine. Is that good or bad?

Bad, and this surprises almost everyone. A well kept pool has very little smell. That sharp swimming pool smell people call chlorine is mostly the smell of chloramines, which means it is the smell of a pool that needs attention rather than a pool that has been cleaned thoroughly.

It builds up worst indoors, where the gas that comes off the water is not carried away and simply sits above the surface, which is exactly the layer a child's face is in. If you walk in and the smell hits you, that is a reasonable moment to say something to the lifeguard or the pool operator, and it is a reasonable evening to keep a child with asthma out of the water.

What do I do the evening it happens?

Very little, and simple things. For ordinary chloramine irritation, get your child out of the swimwear, into a proper shower, and rinse the face and eyelids with clean water. Then a cool cloth held over the closed eyes for a few minutes, which settles the stinging faster than anything else you have at home.

The rule for the rest of the evening is that nobody rubs. Rubbing a stinging eye adds an angry, swollen surface to an eye that would have settled on its own. Cool cloth, distraction, an early bedtime.

If the eye turns out to be an infection, the home care is a little different. Crusts on the lashes come off with cooled boiled water on a clean piece of cotton wool, one piece per eye, wiping gently along the lashes. A cold flannel over the eyes helps the discomfort here too. What I would not do is put anything else into a child's eye without being told to by a doctor, and that includes drops from the pharmacy shelf and anything from the kitchen.

Do goggles actually help?

For the chloramine problem, yes, and it is the single most effective thing on this list. A goggle that seals keeps the water off the surface of the eye altogether, and a child who swims twice a week in goggles usually stops coming home with red eyes. Get a pair that fits a child's face rather than a shrunken adult pair, and let your child choose them, because the pair they like is the pair they wear.

I am more careful about what I claim for infection. Goggles keep water out of the eye, which cannot hurt, and I recommend them for that reason. But an infection also travels on hands, towels and face cloths, so goggles are not a reason to relax the ordinary rules about sharing.

One thing goggles cannot do is protect the eyes from the sun at an outdoor pool, where the water reflects a great deal of it upward. That is a separate problem with a separate answer, and sun protection for children's eyes covers it.

When do we stop swimming?

When the eye is sticky or gluey, stop until it has settled, because that is the kind that spreads. Stop sharing towels, face cloths and pillows at the same time, wash the pillowcases and face cloths in hot water and detergent, and make handwashing the household rule for a few days. It is a nuisance for a week and it saves the whole family catching it in turn.

Stay out of the water entirely if your child has diarrhoea. That is not about eyes at all, it is about what gets into a pool from an unwell swimmer, and the wait after one particular infection is a fortnight after the diarrhoea has completely stopped. Your doctor will tell you if that applies.

Come and be seen rather than waiting it out if there is pain rather than discomfort, if bright light is hurting, if the vision is blurred, or if the redness is getting worse after two or three days instead of better. Pink eye in children goes through what is treated and what is left alone, and a red eye that is also painful and light-sensitive is never something to manage at home. If the lid itself is swelling rather than just red, a swollen eyelid has its own set of rules about urgency.

How do we stop this happening every week?

Goggles for your child, and pool manners for everybody. The pool manners are not etiquette. They are the reason there is less to react with in the water, and they work only if most people do them.

• A one minute shower before getting in. That removes most of the dirt, sweat and oils that use up the pool chemicals.
• Toilet before swimming, and no urinating in the pool. Urine is one of the things chlorine reacts with to make the smell.
• Take small children to the toilet every hour rather than waiting to be asked.
• Change nappies away from the poolside, not on the edge.
• Nobody swims with diarrhoea, and nobody swims with a sticky eye.
• If the pool smells strong or looks cloudy, tell the operator, and swim another day.

Doing all of that will not make a swimming pool a sterile place, and it does not need to be. It will take a child who used to come out of every session with pink stinging eyes and turn swimming back into what it should be, which is the thing that tires them out enough to sleep properly. That is a reasonable thing to want, and it is usually two changes away: a pair of goggles that fit, and a shower before the water.

Common questions

References

1. US Centers for Disease Control and Prevention · Preventing eye irritation from pool chemicals · www.cdc.gov
2. US Centers for Disease Control and Prevention · Preventing illness while swimming · www.cdc.gov
3. NHS · Conjunctivitis · www.nhs.uk
4. American Academy of Ophthalmology · Pink eye (conjunctivitis) · www.aao.org
5. American Academy of Pediatrics, HealthyChildren · Pink eye (conjunctivitis) · www.healthychildren.org

By Dr Chan Li Yen. General information only. It does not replace a consultation. If you are worried about your child's eyes or vision, please see an eye doctor.