Swimmer's Itch

What is Swimmer's Itch?

Swimmer's itch, also called cercarial dermatitis, appears as a skin rash caused by an allergic reaction to certain parasites found in lakes, rivers, ponds and oceans.

Swimmer's itch is found throughout the world and is more frequent during summer months.

Who is at risk for swimmer's itch?

Anyone who swims or wades in natural water may be at risk. Larvae are more likely to be present in shallow water by the shoreline. Children are most often affected because they tend to swim, wade, and play in the shallow water more than adults. Also, they are less likely to towel dry themselves when leaving the water.

How does water become infested with the parasite?

The parasites are passed in the feces of infected birds such as ducks, geese, gulls, swans, and certain aquatic mammals such as muskrats and beavers. Parasite larvae swim in the water in search of a certain aquatic snail. Rather than finding a host bird or mammal, the larvae from an infected snail instead burrows into the nearby swimmer's skin, causing an allergic reaction and rash. Because these larvae cannot develop inside a human, they soon die.

What are the signs and symptoms of swimmer's itch?

Symptoms of swimmer's itch may include:

• Tingling, burning, or itching of the skin
• Small reddish pimples
• Small blisters

Within minutes to days after swimming in contaminated water, you may experience tingling, burning, or itching of the skin. Small reddish pimples appear within twelve hours. Pimples may develop into small blisters. Scratching the areas may result in more infections. Itching may last up to a week or more, but will gradually go away.

The more often you swim or wade in contaminated water, the more likely you are to develop symptoms. Be aware that swimmer's itch is not the only rash that may occur after swimming in natural water.

What should I do if I have symptoms of swimmer's itch?

Try not to scratch. Scratching may cause the rash to become infected. If itching is severe, your health care provider. Most cases of swimmer's itch do not require medical attention. If you have a rash, try the following for relief:

• Use corticosteroid cream
• Apply cool compresses to the affected areas
• Bathe in Epson salts or baking soda
• Soak in colloidal oatmeal baths, such as Aveeno^®
• Apply baking soda paste to the rash (made by stirring water into baking soda until it reaches a paste-like consistency)
• Use an anti-itch lotion, such as Calamine lotion

Can swimmer's itch be spread from person-to-person?

Swimmer's itch is not contagious and cannot be spread from one person to another.

What can be done to reduce the risk of swimmer's itch?

• Do not swim in areas where swimmer's itch is a known problem or where signs have been posted warning of unsafe water.
• Do not swim near or wade in marshy areas where snails are commonly found.
• Towel dry or shower immediately after leaving the water.
• Do not attract birds (e.g., by feeding them) to areas where people are swimming.