Exposure to chlorine can cause a dry, sore rash that may burn or itch. Over-the-counter products such as hydrocortisone cream and antihistamines can help treat the rash.

Chlorine is a chemical people use to disinfect pools and hot tubs. This chemical can significantly irritate the skin, eyes, and respiratory system.

A chlorine rash is a type of contact dermatitis that happens after chlorine exposure. It is easy to confuse a chlorine rash with “swimmer’s itch” or a heat rash.

A chlorine rash develops after the skin comes into contact with chlorine.

It is not possible to be allergic to chlorine, which does not trigger the immune system to produce the proteins that cause allergic reactions. Instead, chlorine is an irritant that can cause symptoms similar to allergic reactions. Some people’s skin may be more sensitive to the chemical than others.

A person who develops a rash after contact with chlorine is experiencing a condition called contact dermatitis. As with other irritants that cause contact dermatitis, chlorine exposure can result in an itchy, inflamed rash and raw, swollen skin.

A person may also experience sore eyes or symptoms of respiratory irritation, such as frequent coughing or sneezing.

Not everyone who swims in a chlorinated pool or sits in a chlorinated hot tub will develop a rash. Chlorine rashes are most common after repeated exposure.

The symptoms of a chlorine rash can vary in intensity from person to person. They are similar to symptoms of rashes caused by other irritants.

Chlorine rash symptoms can include:

  • inflamed skin (redness or other color changes)
  • tenderness and itchiness at the rash site
  • scaly or crusty skin
  • sore skin lesions

A contact dermatitis rash may develop hours or even days after exposure, making it difficult to determine the cause. However, a chlorine rash will worsen with repeated chlorine exposure.

Chlorine is not responsible for every rash that forms after swimming. This section examines other possible causes of rashes after swimming.

Swimmer’s itch

Cercarial dermatitis (swimmer’s itch) is unrelated to chlorine exposure. Instead, it is an allergic reaction to a parasite that snails with an infection release into bodies of water.

People only develop swimmer’s itch after swimming in unchlorinated water, as chlorine would kill the parasites.

Symptoms of swimmer’s itch include:

Symptoms of swimmer’s itch develop very soon after exposure to the parasite. Pimples appear within 12 hours and may develop into small blisters.

Hot tub rash

Pseudomonas folliculitis, also known as “hot tub rash,” can develop when a person experiences prolonged exposure to contaminated water from sitting in a hot tub.

The high temperature in a hot tub can break down the chlorine, allowing bacteria, usually Pseudomonas aeruginosa, to grow in the water. The bacteria causes a skin infection that can lead to an itchy rash that is worse in areas covered by a person’s swimsuit.

A hot tub rash can also cause inflamed, pus-filled blisters to form around hair follicles.

Heat rash

It can be easy to confuse a chlorine rash with heat rash. A person can get heat rash from sitting in a hot tub or swimming in a very warm body of water.

The symptoms can be similar. Heat rash causes small, itchy, prickly bumps on the skin.

People can treat chlorine rash at home with over-the-counter (OTC) products.

At-home treatment for a chlorine rash can involve:

  • a cream containing hydrocortisone to soothe the itch and reduce swelling
  • a cream containing an antihistamine to reduce the itching and inflammation associated with hives
  • a body wash or lotion designed to remove or protect against chlorine

Taking the following steps can help prevent a chlorine rash. These tips may be especially useful for people who know they are sensitive to the chemical:

  • showering immediately before and after swimming in a chlorinated pool
  • removing and rinsing the swimsuit right away and changing into loose, dry clothes
  • spacing out periods of chlorine exposure to give the skin time to heal
  • only spending limited amounts of time in chlorinated water
  • refraining from swimming in overly chlorinated pools

Most chlorine rashes do not require a doctor’s care. However, if a person has a severe reaction, they should contact a doctor immediately.

Doctors can prescribe stronger steroid creams to help the rash heal.

If a rash is not responding to over-the-counter treatments and the person has had no further contact with chlorine, it may also be a good idea to speak with a doctor. The rash may have a different underlying cause.

While the prospect of a chlorine rash may dampen the fun of swimming, most of these rashes are not serious.

People can prevent chlorine rashes by showering before and after swimming to minimize exposure to the chemicals. A person can treat this type of rash using OTC creams.

If a rash is causing concern or not responding to home treatments, it is best to consult a doctor, who can identify the underlying cause and provide stronger medication if needed.

A chlorine rash can happen after exposure to chlorine in swimming pools. This type of rash is a form of contact dermatitis, which can cause inflamed, itchy, and scaly skin.

A person can usually treat a chlorine rash at home without a doctor’s care. To reduce the symptoms, people can use several OTC treatments, including antihistamines and hydrocortisone cream.

Showering immediately after swimming and trying to avoid chlorine as much as possible can help prevent a chlorine rash.