Swimmer’s Itch

What is swimmer’s itch?
How do you get swimmer’s itch?
How does it affect your health?
How can swimmer’s itch be prevented?
How can I treat swimmer’s itch?
Is there anything else I should know?

What is swimmer’s itch?

Swimmer’s itch is a skin rash caused by small larvae found in certain lakes and rivers.

These larvae are called “cercariae”. They are so tiny that it is hard to see them with the naked eye.

When you are out swimming or wading, cercariae can stick to your skin until you get out of the water. Out in the sunshine, the skin dries and the cercariae bite to penetrate your skin. They die afterwards.

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How do you get swimmer’s itch?

1. Waterfowl are the hosts for the parasite that causes the presence of cercariae in the water you swim in.
2. The cycle begins with bird feces that are the source of contamination for the snails along the shore.
3. The cercariae emerge from the snails and return to contaminate the birds.
4. Unfortunately, the cercariae do not distinguish between birds and people. Therefore, people in the water are bitten by accident.

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How does it affect your health?

Swimmer’s itch can be disagreeable to those who have it:

• Soon after you leave the water, small red spots appear on your skin;
• These spots can appear on all the uncovered parts of your body exposed to the water;
• A few hours later, the red spots will have swollen up to resemble insect bites that can grow as big as a dime;
• Intense itchiness sets in and can last for more than 10 days, but it generally disappears in a week or two;
• Some people may suffer minor skin infections.

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How can swimmer’s itch be prevented?

• You may choose not to swim in waters when cases of swimmer’s itch have been reported.
• Spend no more than a few minutes in the water.
• When you leave the water, vigorously rub yourself dry with a towel. Do not let the water evaporate off your skin out in the sun.
• Swim in deeper water if possible.
• The use of sunscreen may prevent the parasites from getting into your skin.
• Do not feed the birds.

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How can I treat swimmer’s itch?

1. First of all, do not scratch or you may cause a skin infection.
2. To relieve the itching, you can use a cream or lotion with calamine or a similar agent. If in doubt, talk to your pharmacist.
3. If the itching continues more than a few days or if you are worried about your health, contact your doctor.

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Is there anything else I should know?

• In spite of the rash and the itching, swimmer’s itch is not a significant health problem.
• Swimmer’s itch cannot be spread from one person to another.
• There is no relation between swimmer’s itch and water pollution.

For more information on Swimmer’s Itch call Ottawa Public Health at 613-580-6744.