A 33-year-old man presents with a 2-week history of itchy bumps on his arms and legs. His medical history is significant for ulcerative colitis, for which he is currently taking mesalamine. He lives alone and does not have pets. He has a hot tub, which he uses regularly. Examination reveals multiple erythematous papules on his extremities. At the patient’s insistence, a shave biopsy is performed.
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Pseudomonas folliculitis or hot tub folliculitis is a common skin condition characterized by inflammation of the hair follicles. It is caused by exposure to the bacterium Pseudomonas aeruginosa. P. aeruginosa can be found in fresh water, in soil, and on human skin. It has also been found in carpeted areas surrounding pools or spas.1,2 The rash associated with folliculitis typically develops within hours but may take as long as 14 days to appear.3
Patients present with itchy, red macules that progress to papules and pustules. The rash can develop in any area exposed to water and may be most prominent on those sites that come in direct contact with a swimsuit. Pseudomonas folliculitis is a self-limiting condition that usually resolves within 10 days.3 Lesions heal without scarring but may leave areas of desquamation or hyperpigmentation.
Because the condition resolves spontaneously, treatment is geared toward short-term symptomatic relief. P. aeruginosa pose no threat to individuals who have immunocompromise and therefore the administration of oral antibiotics is not warranted. Patients should be instructed to clean their hot tubs or spas thoroughly before further use. Guidelines for the proper concentration of chlorine and bromine are available from the Centers for Disease Control and Prevention.4
Rebecca Geiger, PA-C, is a physician assistant at the DermDox Dermatology Center in Hazleton, Pennsylvania. Stephen Schleicher, MD, is an associate professor of medicine at the Commonwealth Medical College in Scranton, Pennsylvania, and an adjunct assistant professor of dermatology at the Perelman School of Medicine at the University of Pennsylvania in Philadelphia. He practices dermatology at the DermDox Dermatology Center in Hazleton, Pennsylvania.
- Wolff K, Johnson RA, Saavedra AP. Fitzpatrick’s Color Atlas and Synopsis of Clinical Dermatology. 7th ed. New York, NY: McGraw Hill; 2013:568.
- Silverman AR, Nieland ML. Hot tub dermatitis: a familial outbreak of Pseudomonas folliculitis. J Am Acad Dermatol. 1983;8:153-156.
- Yu Y, Cheng AS, Wang L, Dunne WM, Bayliss SJ. Hot tub folliculitis or hot hand-foot syndrome caused by Pseudomonas aeruginosa. J Am Acad Dermatol. 2007;57:596-600.
- Centers for Disease Control and Prevention. Healthy Swimming. Residential Pool or Hot Tub Owners. https://www.cdc.gov/healthywater/swimming/residential/index.html. Updated May 4, 2016. Accessed April 11, 2017.