Swimmer's Itch (Cercarial Dermatitis Schistosomal Dermatitis)

What is swimmer's itch?

Swimmers itch is a skin rash caused by certain parasites of birds and mammals. The parasite is carried in the intestines of waterfowl and aquatic mammals. Snails become infected with the parasites and release larvae into the water. The larvae search out a suitable host. The itch occurs when the larvae accidentally penetrate human skin rather than their natural hosts. The allergic reaction of swimmer's itch can be extremely annoying but is not likely to be dangerous and will not spread. However, scratching the itch could cause infection. Swimmer's itch occurs throughout New York State and many other regions.

Who gets swimmer's itch?

People who swim or wade in infested water may experience this itching rash.

How is swimmer's itch spread?

The swimmer may get the infection by swimming or wading in infested water and then allowing water to evaporate off the skin rather than briskly drying the skin with a towel. Person to person spread does not occur.

What are the symptoms of swimmer's itch?

The first signs of swimmer's itch are noticeable soon after you get out of the water. Once dry, you will detect tingling sensations on exposed parts of your body. The next sign is the development of small red spots where the organism has penetrated through your skin. Hours later, the tingling sensation will cease and red spots will enlarge and become itchy. The itching stage usually disappears within a week.

What is the treatment for swimmer's itch?

Most cases of swimmer's itch do not require treatment. However, corticosteroid creams, calamine lotion and colloidal oatmeal baths can be used to minimize the itching. It's important not to scratch, because scratching may cause the rash to become infected. If itching is severe, contact your health care provider who may prescribe lotion or creams to lessen your symptoms.

How can swimmer's itch be prevented?

  • Towel down briskly right after leaving the water to help remove the parasites; sometimes the parasites can be rubbed off before they fully penetrate the skin.
  • Take a shower immediately and dry off briskly after leaving the beach.
  • Do not feed waterfowl. Feeding waterfowl may aggravate the problem by concentrating potential hosts in a limited area.