Melissa Magstadt, South Dakota Secretary of Health


(cercarial dermatitis, schistosome dermatitis)

South Dakota Department of Health
Office of Disease Prevention Services - 605-773-3737 — (1-800-592-1861 in South Dakota only)
This material is provided for informational purposes only and is not a substitute
for medical care. We are not able to answer personal medical questions. Please see your
health care provider concerning appropriate care, treatment or other medical advice.

What is swimmer's itch?
Swimmers itch is a skin rash caused by certain parasites of birds and mammals. These parasites are released from infected snails and migrate through waters including those used for recreational swimming.

Who gets swimmer's itch?
People who swim or wade in infected water may experience this itching rash. All age groups and both sexes can be involved, but children are most infected due to their habits of swimming or wading in the water and playing on the beach as the water evaporates from the skin.

How is swimmer's itch spread?
The victim may get the infection by swimming or wading in infested water and then allowing water to evaporate off the skin rather than regularly drying the skin with a towel. Person to person spread does not occur.

What are the symptoms of swimmer's itch?
Whenever infested water is allowed to evaporate off the skin, an initial tingling sensation may be felt associated with the penetration of the parasite into the skin. The itching will subside for 10-15 hours and may then become extremely intense. This itching stage usually disappears within a week.

How soon do the symptoms begin?
A victim's first exposure to infested water may not result in the itchy rash. Repeated exposure increases a person's sensitivity to the parasite and increases the likelihood of rash development. Symptoms may appear within one to two hours of exposure.

What is the treatment for swimmer's itch?
While all cases do not require treatment, some people may seek relief by applying specific skin lotions or creams to minimize the itching.

What can be done to prevent the spread of swimmer's itch?
Toweling off after swimming or wading in infested water can be very helpful in preventing rash development. Copper sulfate or copper carbonate materials can be applied by boat around popular bathing areas. If properly timed, these applications may prevent the annual migration of infested snails into swimming areas.

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