Hot Tub Rash (Pseudomonas dermatitis / Folliculitis)

Note: PDFs related to this topic are also available: Facts About "Hot Tub Rash"

[PDF - 956 kb] and Datos sobre la "foliculitis de la bañera" y el "oído de nadador" (Pseudomonas)

[PDF - 804 kb] (translation courtesy of the New Mexico Department of Public Health).
Below are answers to the most common questions regarding hot tub rash and healthy swimming.

What is Hot Tub Rash?

Hot tub rash, or dermatitis, is an infection of the skin. Symptoms of hot tub rash include:

Itchy spots on the skin that become a bumpy red rash.
The rash is worse in areas that were previously covered by a swimsuit.
Pus-filled blisters around hair follicles.

Hot tub rash can affect people of all ages.

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What Causes Hot Tub Rash?

Hot tub rash is often caused by infection with the germ Pseudomonas aeruginosa.
This germ is common in the environment (for example, in the water and soil) and is microscopic, so it can’t be seen with the naked eye.

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How is Hot Tub Rash Spread at Recreational Water Venues?

Hot tub rash can occur if contaminated water comes in contact with skin for a long period of time.
The rash usually appears within a few days of being in a poorly maintained hot tub (or spa), but it can also appear within a few days after swimming in a poorly maintained pool or contaminated lake.
Most rashes clear up in a few days without medical treatment. However, if your rash lasts longer than a few days, consult your health care provider.

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How Do I Protect Myself and My Family?

Because hot tubs have warmer water than pools, chlorine or other disinfectants used to kill germs (like Pseudomonas aeruginosa) break down faster. This can increase the risk of hot tub rash infection for swimmers.
To reduce the risk of hot tub rash:

Remove your swimsuit and shower with soap after getting out of the water.
Clean your swimsuit after getting out of the water.
Ask your pool/hot tub operator if disinfectant (for example, chlorine) and pH levels are checked at least twice per day—hot tubs and pools with good disinfectant and pH control are less likely to spread germs.
Use pool test strips to check the pool or hot tub yourself for adequate disinfectant (chlorine or bromine) levels. CDC recommends for pools [PDF - 106 kb] and hot tubs [PDF - 98 kb] that:
- Pools: free chlorine (1—3 parts per million or ppm)
- Hot Tubs: free chlorine (2—4 ppm) or bromine (4—6 ppm).
- Both hot tubs and pools should have a pH level of 7.2—7.8.
- If you find improper chlorine, bromine, and/or pH levels, tell the hot tub/pool operator or owner immediately.

Four Questions to Ask Your Hot Tub Operator

What was the most recent health inspection score for the hot tub?
Are disinfectant and pH levels checked at least twice per day?
Are disinfectant and pH levels checked more often when the hot tub is being used by a lot of people?
Are the following maintenance activities performed regularly:
- Removal of the slime or biofilm layer by scrubbing and cleaning?
- Replacement of the hot tub water filter according to manufacturer’s recommendations?
- Replacement of hot tub water?

For further information on protecting yourself and others when using pools and hot tubs, please see the For Swimmers and Hot Tub Users page.