University of Minnesota Extension
 Menu  Menu

Extension > Environment > Water Resources > Shoreland > What is swimmer's itch and how can I avoid it?

Print Email Share

What is swimmer's itch and how can I avoid it?

Barb Liukkonen, Ext. Ed.-Shoreland Management

What is Swimmers' Itch?

Swimmer's itch is common around Minnesota's lakes in midsummer. Red, itchy welts appear on your skin within several hours of leaving the water. It may last a few days to several weeks, depending on your sensitivity.

How can I avoid Swimmers' Itch?

Reduce your chances of getting severe swimmers' itch by following these simple guidelines.

Where does Swimmers' Itch come from?

Swimmer's itch comes from a microscopic parasite (Schisosome cercariae) that has a complex life cycle involving water birds or mammals, snails, and free-swimming stages. During one of its free-swimming stages, humans can be exposed to the parasites in lake water. When a swimmer leaves the water and water drops begin to evaporate, the tiny parasites burrow into the skin to try to survive. Where water is held near the skin (at waistbands and leg openings) the parasites have more time to burrow in.

People cannot become a host for the parasite, either through skin penetration or by swallowing lake water because the parasites are killed by the body's natural defense mechanisms.

Is there any treatment?

Some sunscreens and lotions may reduce the infections, although nothing is known to be completely effective. If you get swimmers' itch, lotions or ointments may relieve the itching. In severe cases, you may need to consult a physician.

  • © 2016 Regents of the University of Minnesota. All rights reserved.
  • The University of Minnesota is an equal opportunity educator and employer. Privacy