Clinical Study
Swimming Related Infections: What Clinicians Should Know
Allie Priego, PA-C • July 7, 2025
As temperatures rise, so do visits to pools, lakes, and oceans. But for clinicians, summer means something else: an uptick in infections linked to swimming and water exposure.
While most people enjoy water safely, we know that certain exposures can lead to infections, which can range from mild to severe, particularly for certain patient populations, such as immuno-compromised individuals. Here’s a seasonal refresher to help you recognize and manage the most common swimming-related infections that might come through your clinic doors.
Otitis Externa (Swimmer’s Ear)
“Swimmer’s ear” is a common summer complaint, in particular for children. This is typically caused by Pseudomonas or Staph aureus, and recent water submersion can be the inciting event. Water exposure increases the risk of Otitis externa by disrupting the protective cerumen barrier, increasing canal moisture, and facilitating pathogen entry.1
- Topical treatment usually does the trick for most cases of otitis externa.
- Be aware of severe pain, fever, or immunocompromised patients—these may require oral antibiotics or further ENT evaluation.
Diarrheal Illness
Not all cases of post-swimming diarrhea are viral. Cryptosporidium is chlorine-resistant and one of the leading causes of waterborne gastrointestinal (GI) outbreaks. The highest rates of reported Cryptosporidiosis in the US occur in young children aged 1–4 years and in adults aged 15–44 years.2 In 2024, HealthTrackRx had a 0.9% positivity rate for Cryptosporidium from our diarrheal panels.
- Symptoms often include prolonged watery diarrhea lasting more than a week.2
- Other pathogens to consider: Giardia, norovirus, Shigella, coli (ETEC).
- Ask about waterpark visits, lake swims, or accidental swallowing of pool water.
- Consider ordering a GI PCR panel or O&P if diarrhea persists.
Contact Lens Keratitis
The risk of keratitis is markedly increased by water exposure, particularly swimming with contact lenses, due to the introduction of waterborne pathogens. Swimming with contact lenses raises the risk of Acanthamoeba or Pseudomonas keratitis—both vision-threatening if missed.3 In 2024, HealthTrackRx had a positivity rate of 1.3% for Acanthaemoeba and 2.5% positivity rate for Pseudomonas via our ophthalmology test panel.
- Red flag symptoms: pain out of proportion to exam, blurred vision, photophobia.3
- Prompt referral to ophthalmology is essential with cases of Acanthamoeba or Pseudomonas
- Discuss prevention strategies, which include strict avoidance of water exposure (no swimming, showering, or rinsing lenses/cases with water), meticulous hand and lens hygiene, and regular replacement of lens cases.
Folliculitis (Hot Tub Folliculitis)
Pseudomonas aeruginosa is a frequent offender in hot tubs and pools, often causing folliculitis. This self-limiting rash typically resolves within a few days without specific therapy in most cases.4 In 2024, HealthTrackRx had a 3.4% positivity rate for Pseudomonas aeruginosa from our wound panels.
- Consider topical antibiotics (e.g., mupirocin or clindamycin) if lesions persist, recur, or show no improvement with conservative measures.4
- Not all rashes are benign: cellulitis or wound infections after swimming—especially in saltwater or brackish water—should prompt you to consider Vibrio vulnificus.5
- At-risk patients? Think of patients with diabetes and anyone with open wounds with recent water exposure.4
References
- Rosenfeld, R. M., Schwartz, S. R., Cannon, C. R., Roland, P. S., Simon, G. R., Kumar, K. A., Huang, W. W., Haskell, H. W., & Robertson, P. J. (2014). Clinical practice guideline: acute otitis externa. Otolaryngology–Head and Neck Surgery: Official Journal of American Academy of Otolaryngology-Head and Neck Surgery, 150(1 Suppl), S1–S24. https://doi.org/10.1177/0194599813517083
- Centers for Disease Control and Prevention. (n.d.-a). Post-travel diarrhea. Centers for Disease Control and Prevention. https://www.cdc.gov/yellow-book/hcp/post-travel-evaluation/post-travel-diarrhea.html
- Cabrera-Aguas, M., Khoo, P., & Watson, S. L. (2022). Infectious keratitis: A review. Clinical & Experimental Ophthalmology, 50(5), 543–562. https://doi.org/10.1111/ceo.14113
- Stevens, D. L., Bisno, A. L., Chambers, H. F., Dellinger, E. P., Goldstein, E. J., Gorbach, S. L., Hirschmann, J. V., Kaplan, S. L., Montoya, J. G., & Wade, J. C. (2014). Practice guidelines for the diagnosis and management of skin and soft tissue infections: 2014 update by the Infectious Diseases Society of America. Clinical Infectious Diseases: An Official Publication of the Infectious Diseases Society of America, 59(2), 147–159. https://doi.org/10.1093/cid/ciu296
- Baker-Austin, C., Oliver, J. D., Alam, M., Ali, A., Waldor, M. K., Qadri, F., & Martinez-Urtaza, J. (2018). Vibrio spp. infections. Nature Reviews. Disease Primers, 4(1), 8. https://doi.org/10.1038/s41572-018-0005-8
References
- Rosenfeld, R. M., Schwartz, S. R., Cannon, C. R., Roland, P. S., Simon, G. R., Kumar, K. A., Huang, W. W., Haskell, H. W., & Robertson, P. J. (2014). Clinical practice guideline: acute otitis externa. Otolaryngology–Head and Neck Surgery: Official Journal of American Academy of Otolaryngology-Head and Neck Surgery, 150(1 Suppl), S1–S24. https://doi.org/10.1177/0194599813517083
- Centers for Disease Control and Prevention. (n.d.-a). Post-travel diarrhea. Centers for Disease Control and Prevention. https://www.cdc.gov/yellow-book/hcp/post-travel-evaluation/post-travel-diarrhea.html
- Cabrera-Aguas, M., Khoo, P., & Watson, S. L. (2022). Infectious keratitis: A review. Clinical & Experimental Ophthalmology, 50(5), 543–562. https://doi.org/10.1111/ceo.14113
- Stevens, D. L., Bisno, A. L., Chambers, H. F., Dellinger, E. P., Goldstein, E. J., Gorbach, S. L., Hirschmann, J. V., Kaplan, S. L., Montoya, J. G., & Wade, J. C. (2014). Practice guidelines for the diagnosis and management of skin and soft tissue infections: 2014 update by the Infectious Diseases Society of America. Clinical Infectious Diseases: An Official Publication of the Infectious Diseases Society of America, 59(2), 147–159. https://doi.org/10.1093/cid/ciu296
- Baker-Austin, C., Oliver, J. D., Alam, M., Ali, A., Waldor, M. K., Qadri, F., & Martinez-Urtaza, J. (2018). Vibrio spp. infections. Nature Reviews. Disease Primers, 4(1), 8. https://doi.org/10.1038/s41572-018-0005-8
Medical Science Liaison
Related Articles and White papers
Allie Priego, PA-C • July 7, 2025
As temperatures rise, so do visits to pools, lakes, and oceans. But for clinicians, summer means something else: an uptick in infections linked to swimming and water exposure.
While most people enjoy water safely, we know that certain exposures can lead to infections, which can range from mild to severe, particularly for certain patient populations, such as immuno-compromised individuals. Here’s a seasonal refresher to help you recognize and manage the most common swimming-related infections that might come through your clinic doors.
Otitis Externa (Swimmer’s Ear)
“Swimmer’s ear” is a common summer complaint, in particular for children. This is typically caused by Pseudomonas or Staph aureus, and recent water submersion can be the inciting event. Water exposure increases the risk of Otitis externa by disrupting the protective cerumen barrier, increasing canal moisture, and facilitating pathogen entry.1
- Topical treatment usually does the trick for most cases of otitis externa.
- Be aware of severe pain, fever, or immunocompromised patients—these may require oral antibiotics or further ENT evaluation.
Diarrheal Illness
Not all cases of post-swimming diarrhea are viral. Cryptosporidium is chlorine-resistant and one of the leading causes of waterborne gastrointestinal (GI) outbreaks. The highest rates of reported Cryptosporidiosis in the US occur in young children aged 1–4 years and in adults aged 15–44 years.2 In 2024, HealthTrackRx had a 0.9% positivity rate for Cryptosporidium from our diarrheal panels.
- Symptoms often include prolonged watery diarrhea lasting more than a week.2
- Other pathogens to consider: Giardia, norovirus, Shigella, coli (ETEC).
- Ask about waterpark visits, lake swims, or accidental swallowing of pool water.
- Consider ordering a GI PCR panel or O&P if diarrhea persists.
Contact Lens Keratitis
The risk of keratitis is markedly increased by water exposure, particularly swimming with contact lenses, due to the introduction of waterborne pathogens. Swimming with contact lenses raises the risk of Acanthamoeba or Pseudomonas keratitis—both vision-threatening if missed.3 In 2024, HealthTrackRx had a positivity rate of 1.3% for Acanthaemoeba and 2.5% positivity rate for Pseudomonas via our ophthalmology test panel.
- Red flag symptoms: pain out of proportion to exam, blurred vision, photophobia.3
- Prompt referral to ophthalmology is essential with cases of Acanthamoeba or Pseudomonas
- Discuss prevention strategies, which include strict avoidance of water exposure (no swimming, showering, or rinsing lenses/cases with water), meticulous hand and lens hygiene, and regular replacement of lens cases.
Folliculitis (Hot Tub Folliculitis)
Pseudomonas aeruginosa is a frequent offender in hot tubs and pools, often causing folliculitis. This self-limiting rash typically resolves within a few days without specific therapy in most cases.4 In 2024, HealthTrackRx had a 3.4% positivity rate for Pseudomonas aeruginosa from our wound panels.
- Consider topical antibiotics (e.g., mupirocin or clindamycin) if lesions persist, recur, or show no improvement with conservative measures.4
- Not all rashes are benign: cellulitis or wound infections after swimming—especially in saltwater or brackish water—should prompt you to consider Vibrio vulnificus.5
- At-risk patients? Think of patients with diabetes and anyone with open wounds with recent water exposure.4
References
- Rosenfeld, R. M., Schwartz, S. R., Cannon, C. R., Roland, P. S., Simon, G. R., Kumar, K. A., Huang, W. W., Haskell, H. W., & Robertson, P. J. (2014). Clinical practice guideline: acute otitis externa. Otolaryngology–Head and Neck Surgery: Official Journal of American Academy of Otolaryngology-Head and Neck Surgery, 150(1 Suppl), S1–S24. https://doi.org/10.1177/0194599813517083
- Centers for Disease Control and Prevention. (n.d.-a). Post-travel diarrhea. Centers for Disease Control and Prevention. https://www.cdc.gov/yellow-book/hcp/post-travel-evaluation/post-travel-diarrhea.html
- Cabrera-Aguas, M., Khoo, P., & Watson, S. L. (2022). Infectious keratitis: A review. Clinical & Experimental Ophthalmology, 50(5), 543–562. https://doi.org/10.1111/ceo.14113
- Stevens, D. L., Bisno, A. L., Chambers, H. F., Dellinger, E. P., Goldstein, E. J., Gorbach, S. L., Hirschmann, J. V., Kaplan, S. L., Montoya, J. G., & Wade, J. C. (2014). Practice guidelines for the diagnosis and management of skin and soft tissue infections: 2014 update by the Infectious Diseases Society of America. Clinical Infectious Diseases: An Official Publication of the Infectious Diseases Society of America, 59(2), 147–159. https://doi.org/10.1093/cid/ciu296
- Baker-Austin, C., Oliver, J. D., Alam, M., Ali, A., Waldor, M. K., Qadri, F., & Martinez-Urtaza, J. (2018). Vibrio spp. infections. Nature Reviews. Disease Primers, 4(1), 8. https://doi.org/10.1038/s41572-018-0005-8
References
- Rosenfeld, R. M., Schwartz, S. R., Cannon, C. R., Roland, P. S., Simon, G. R., Kumar, K. A., Huang, W. W., Haskell, H. W., & Robertson, P. J. (2014). Clinical practice guideline: acute otitis externa. Otolaryngology–Head and Neck Surgery: Official Journal of American Academy of Otolaryngology-Head and Neck Surgery, 150(1 Suppl), S1–S24. https://doi.org/10.1177/0194599813517083
- Centers for Disease Control and Prevention. (n.d.-a). Post-travel diarrhea. Centers for Disease Control and Prevention. https://www.cdc.gov/yellow-book/hcp/post-travel-evaluation/post-travel-diarrhea.html
- Cabrera-Aguas, M., Khoo, P., & Watson, S. L. (2022). Infectious keratitis: A review. Clinical & Experimental Ophthalmology, 50(5), 543–562. https://doi.org/10.1111/ceo.14113
- Stevens, D. L., Bisno, A. L., Chambers, H. F., Dellinger, E. P., Goldstein, E. J., Gorbach, S. L., Hirschmann, J. V., Kaplan, S. L., Montoya, J. G., & Wade, J. C. (2014). Practice guidelines for the diagnosis and management of skin and soft tissue infections: 2014 update by the Infectious Diseases Society of America. Clinical Infectious Diseases: An Official Publication of the Infectious Diseases Society of America, 59(2), 147–159. https://doi.org/10.1093/cid/ciu296
- Baker-Austin, C., Oliver, J. D., Alam, M., Ali, A., Waldor, M. K., Qadri, F., & Martinez-Urtaza, J. (2018). Vibrio spp. infections. Nature Reviews. Disease Primers, 4(1), 8. https://doi.org/10.1038/s41572-018-0005-8
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