Person shown scratching their right arm, with blue water in the background

This Version Posted: September 9, 2021

Going for a swim in a local lake or waterway? Reduce your risk of Swimmer’s Itch that can surface without warning.

NOTE: The Health Unit’s beach water testing program is completed for another year. It will resume in Summer 2022.


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What is Swimmer’s Itch?
  • A skin rash that causes itching and redness. You can get it while swimming
  • There is no treatment required for Swimmer’s Itch. While the rash is uncomfortable, itching symptoms may continue for several days, before disappearing within several days
  • People are encouraged to avoid scratching if at all possible. Applying skin lotions to the affected areas of the body can provide some relief
  • Swimmer’s Itch affects people of all ages, but children are most often affected since they play or swim in shallow water where the parasite that causes Swimmer’s Itch is most likely to be found
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What is the Cause?
  • Usually caused by a parasite called Shistosomes, which commonly affects birds, semi-aquatic mammals, and snails
  • Parasite will penetrate the skin of people who swim in water infested with Schistosomes (typically in shallow water close to shore). These invisible parasites burrow under the skin and quickly die, causing an allergic reaction (Swimmer’s Itch)
  • It’s hard to predict when and where Swimmer’s Itch will occur. The presence of parasites that cause the condition is based on a number of biological and environmental factors.
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Preventing Swimmer’s Itch
  • Check for warning signs at public beaches, lakes and picnic areas for notices stating swimmer’s itch may be present
  • Before swimming, create a water-proof barrier by applying baby oil, creams containing DEET, Swimmer’s Itch Guard, or similar products on exposed skin to prevent parasite larvae from burrowing into your skin
  • Swim away from the shoreline where the parasite that causes Swimmer’s Itch is most likely to be found. If you are unsure about the water, avoid areas with lots of weed growth (there may be more snails and larvae around aquatic plants)
  • Use a pier or dock to enter the water to help reduce your exposure to parasites near the shore. Make sure these structures are approved for swimming and do not dive into unknown waters
  • Rub your skin with a rough towel as soon as you get out of the water. If water is left to dry on the skin, there is a greater likelihood of developing Swimmer’s Itch.
  • Have a shower with clean water as soon as you leave the lake or river. NOTE: Showering will not remove any larvae that have already burrowed into your skin.
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Additional Resources
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