Is That a Chlorine Rash? What Your Skin Is Telling You

Whether you’re swimming laps, playing Marco Polo or lounging on a float with a good book, being at the pool is all about having fun. And there’s nothing fun about an itchy, red rash.

It’s natural to worry that you’re allergic to chlorine, the disinfectant that makes pool water safe to swim in. But allergist Ronald Purcell, MD, says you can probably set that anxiety aside.

“Chlorine reactions are almost always irritation, not a true allergy,” Dr. Purcell clarifies. Here’s what that means (and what to do about it).

What is a chlorine rash?

A chlorine rash is a type of irritant dermatitis, which is a fancy way of saying that your skin’s reacting to something that’s irritating it — in this case, the chlorine in pool water.

That chlorine keeps you safe from microorganisms that thrive in untreated water, like bacteria, parasites and viruses. But it can still do a number on your skin. While you’re paddling around in the water, that chlorine is stripping your skin of its natural oils (sebum), making it dry and sensitive.

For the same reason, you may also find that pool water bothers your:

• Eyes
• Nose
• Lungs
• Genitals

If you have a breathing condition like asthma, swimming in chlorinated water may make it worse. If so, Dr. Purcell recommends bringing your rescue medication to the pool with you, just to be safe.

(And in case you’re wondering, yes: Saltwater pools have chlorine in them, too.)

What does it look like?

Chlorine rashes are defined more by when and where they show up than by how they look. Like many rashes, an irritant dermatitis from chlorine will usually be:

• Red
• Itchy
• Mildly inflamed
• Spread over larger areas of skin

These rashes can vary because everyone’s skin reacts differently. And if you already have a skin condition, like psoriasis or chronic hives, a chlorine rash can just make your existing rash look (and feel) worse.

“It probably won’t be painful. Just itchy and unpleasant,” Dr. Purcell says.

The best way to know what you’re dealing with is to pay attention to context clues. You can tell it’s chlorine-induced irritant dermatitis if the rash:

• Appears shortly after getting out of the pool — anywhere from a few minutes to a day later
• Only happens when you go swimming
• Doesn’t affect body parts you kept out of the water

How long does a chlorine rash last?

If you leave the pool with a rash from chlorine exposure, rest assured, you won’t be carrying that souvenir around for very long.

“It’ll probably resolve within a couple of hours — a day or two after exposure, at most,” Dr. Purcell says.

Call a healthcare provider if your rash doesn’t go away (or gets worse) within a couple of days. If it’s hanging around, it probably isn’t a chlorine rash.

What causes it

“Skin is supposed to be a barrier,” Dr. Purcell explains. “If that barrier is broken, irritants can get in more easily and cause more inflammation.”

Chlorine can be harsh on sensitive skin. It also reacts with the sweat, dirt and oils on your skin every time you get into the pool. It forms compounds called chloramines, which can be even more irritating than chlorine itself.

“If a pool smells really strong, that often means chlorine has reacted with other substances and formed chloramines,” he continues. It’s one of many reasons why regular pool maintenance is so important for safe swimming. (It’s also a reason you shouldn’t pee in the pool … in case you needed one.)

Who is more likely to get it

There are two main reasons you might be prone to getting chlorine rashes after a dip in the pool:

1. You have a skin condition: From ichthyosis to adult acne, there’s a wide range of skin issues that can make you more sensitive to chlorine. “Eczema is the big one,” Dr. Purcell reports. “When the skin barrier is already broken down, chlorine can trigger a more vigorous reaction.”
2. You swim routinely: If you’re spending lots of time in the pool, whether for fun or competition, you’re facing repeated chlorine exposure. And that’s not all. Those tight-fitting swimsuits and repetitive motions are causing friction. If they damage your skin, you’ll be even more vulnerable to irritant dermatitis.

Chlorine rash vs. allergy

It’s understandable to think that a rash is a sign of a pool water allergy, especially if you’re also dealing with red, itchy eyes or a chlorine cough. But Dr. Purcell says true chlorine allergies are extremely rare.

“Irritant dermatitis is what we’re seeing 99% of the time,” Dr. Purcell says.

When you have an allergic reaction, your immune system is responding to a perceived threat in your environment that isn’t actually dangerous — like pollen or pet dander. That’s usually not what’s happening with a chlorine rash.

Your immune system isn’t mistaking chlorine for a harmful invader. Your skin is actually being harmed. Those irritating pool chemicals are disrupting your skin barrier and triggering inflammation.

So, you probably aren’t allergic to chlorine. But it is possible to have an allergic reaction to something you eat, touch or inhale while you’re at the pool that isn’t pool water. Get help immediately if you develop a rash or hives and are also:

• Vomiting
• Swelling up
• Feeling dizzy or lightheaded
• Having trouble breathing or swallowing

These are signs of a life-threatening allergic reaction called anaphylaxis. Whatever’s causing it, you need immediate treatment.

How to treat it

Chlorine rashes are mild, short-term and don’t usually require treatment.

“If it’s not bothering you, you can often just leave it alone and let it resolve,” Dr. Purcell says. But if you’re itchy or uncomfortable, don’t scratch. That will only make the irritation worse and could even cause an infection.

Dr. Purcell recommends using an over-the-counter (OTC) itch reliever, like:

• An oral antihistamine: During the day, opt for a non-drowsy antihistamine like Cetirizine (Zyrtec®), Loratadine (Claritin®) or Fexofenadine (Allegra®). If itching’s keeping you up at night, consider a diphenhydramine product, like Benadryl®, Unisom® or ZzzQuil®, instead.
• A topical steroid cream: Dr. Purcell says hydrocortisone cream should help you ditch the itch and relieve some of the irritation that comes with a chlorine rash.
• Other topical treatments: Aloe vera and calamine lotion are great options to soothe angry skin. If you want to take another dip, skip the pool and try a calming colloidal oatmeal bath instead.

If over-the-counter treatments aren’t keeping your chlorine rash symptoms in check, call a healthcare provider.

Prevention

The only 100% effective way to avoid chlorine rashes is to stay out of the pool. But there are steps you can take — short of swearing off swim time — to reduce your risk. Dr. Purcell says you lower the odds of skin irritation when you:

• Monitor pool conditions. If it’s your pool that’s giving you a chlorine rash, better upkeep may do the trick. “Make sure the pool chemistry is balanced,” Dr. Purcell advises. “If it’s not well maintained, it’s more likely to cause irritation.”
• Shower before swimming. Imagine your skin is a sponge. When you shower before you swim, it soaks up some of that fresh water, so it takes in less chlorinated pool water later. Rinsing off also washes away sweat and oils that can react with chlorine and create more irritating compounds. “That simple step really helps reduce skin reactions,” Dr. Purcell explains.
• Shower after swimming. Following a dip in the pool with a quick shower cuts down the time the chlorine sits on your skin, drying it out. The sooner you shower after getting out of the pool, the lower the chances you’ll take home a rash as a reminder of your pool day.
• Moisturize. Once you’ve rinsed off the pool water, follow up with a thick moisturizer made to soothe dry, sensitive skin. It’ll lock in that hydration and speed recovery.
• Keep your skin barrier strong. “Maintaining good skin health is key to preventing chlorine rashes,” Dr. Purcell says. That means washing with mild, unscented cleansers, keeping your skin moisturized and protecting it from sun damage.
• Avoid over-scrubbing. That sugar scrub, loofah or pumice stone that leaves you feeling squeaky clean can damage your skin, making it more sensitive to chlorine. If you already have a chlorine rash, harsh exfoliation can worsen the damage.
• Manage chronic conditions. If you have a health condition that affects your skin barrier — like eczema, diabetes, rosacea or chronic kidney disease — tell your specialist about your chlorine rashes. They may be able to help tamp down the dryness and inflammation that makes your skin more prone to them.

Just keep swimming

Swimming is a great source of exercise, stress relief and fun. If the skin irritation you’re experiencing is bad enough to outweigh those benefits, talk to your primary care provider. You may have an underlying allergy or skin condition, unrelated to chlorine, that needs addressing.

Otherwise, Dr. Purcell is decidedly pro-pool.

“Don’t avoid swimming if you enjoy it,” he encourages. “These reactions are manageable and not dangerous. If you’re taking steps to protect your skin and treat the itch, a chlorine rash doesn’t have to ruin your day.”