Disease
Fact Sheet Series:
What is swimmer's itch?
Swimmer's itch is a skin rash caused by a parasite (shistosomes) which
ordinarily infect birds, semi-aquatic mammals, and snails. Common
grackles, red-winged blackbirds, ducks, geese, swans, muskrats and moles
have been found to carry the parasite. As part of their developmental
life-cycle, these parasites are released from infected snails, migrate
through the water, and are capable of penetrating the skin of man. After
penetration, these parasites remain in the skin and die but can cause an
allergic reaction in some people. The parasite in man does not mature,
reproduce or cause any permanent infection.
Who gets swimmer's itch?
Only about one third of the people who come in contact with the
parasite develop swimmer's itch. People who swim or wade in infested water
may experience this itchy rash. All age groups and both sexes can be
involved, but children are most often infected due to their habits of
swimming or wading in shallow water and playing on the beach as the water
evaporates from the skin. Swimmer's itch may be prevalent among bathers in
lakes in many parts of the world, including the Great Lakes region of
North America and certain coastal beaches.
How is swimmer's itch spread?
An individual may get the infection by swimming or wading in infested
water and then allowing water to evaporate off the skin rather than 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 irritated spot reaches its maximum size
after about 24 hours; the itching may continue for several days. The
symptoms should disappear within a week.
How soon do the symptoms begin?
A person's first exposure to infested water may not result in the
itchy rash. Repeated exposure increases a person's allergic sensitivity to
the parasite and increases the likelihood of rash development. Symptoms
may appear within 1 to 2 hours of exposure.
What is the treatment for swimmer's itch?
There is no treatment necessary for swimmer’s
itch. Some people may get relief from the itching by applying skin lotions
or creams to the infected site.
When can you get swimmer's itch?
The first outbreaks usually occur in late May or early June. The
outbreaks in Wisconsin may last from 2 weeks in the northern lakes to a
month in the southern lakes. In some lakes it may last the entire summer.
What can be done to reduce the chances of getting
swimmer's itch?
- Toweling off immediately after swimming or wading in infested water
can be very helpful in preventing rash development.
- Swim in water away from the shore.
- Avoid swimming in areas where snails have accumulated.
Don't encourage birds to stay near swimming areas by feeding them.
For more information, contact your
Local
Public Health Department
Back to Communicable Disease
Fact Sheet Series Index Page
PDF: The free Adobe Reader®
software is needed to view and print portable document format (PDF) files.
Learn more
Last Revised: June 28, 2011
|
