Swimmer’s Itch

With sunny days and warmer weather right around the corner, many people are going out on the boat and getting in the water. Rising air temperatures lead to increased water temperatures and will create optimal conditions for swimmer’s itch.

Swimmer’s itch, or cercarial dermatitis, is most commonly caused from microscopic parasites that can infect birds and mammals. The parasite reproduces within snails and is released into shallow water where the larvae wait for a host to come in contact with such as birds, animals and sometimes humans. In the case of contact with human skin, the parasite will burrow in and will cause an allergic reaction which results in a skin rash. Since humans are not an adequate host for reproduction for the parasite, the larvae will die.

Swimmer’s itch will present as small red pimples and blisters with itching, tingling or burning of the skin. These symptoms can appear within minutes to days after swimming in water containing the parasites. Scratching the area is not recommended as this may result in a secondary bacterial infection. The itching may last up to a week or more, but will gradually subside. It is important to keep in mind swimmer’s itch is not the only rash that can occur after swimming in fresh or salt water.

To reduce the risk of developing swimmer’s itch, it is important to first avoid areas that are known to have swimmer’s itch. Do not attract birds to areas where people swim and do not wade in shallow areas where snails are commonly found. Towel drying or showering immediately after leaving the water will help reduce the likelihood of developing swimmer’s itch. Applying a water repellant substance, such as Vaseline or water proof sunscreen before entering the lake may also help prevent swimmer’s itch.

Most of the time swimmer’s itch can be treated with corticosteroid cream, cool compresses, Epsom salt or baking soda baths, or anti-itch lotions. If itching is severe or if the rash has not subsided within a few days, it may be necessary to see a health care provider.


"Swimmer's Itch FAQs." Centers for Disease Control and Prevention. Centers for Disease Control and Prevention, 10 Jan. 2012. Web. 29 May 2017.

"Swimmer's itch." Swimmer's Itch: Information & Help: Minnesota DNR. N.p., n.d. Web. 29 May 2017.