Swimmer's itch is annoying, harmless

The Westport Weston Health District urges local beach-goers to be on the alert for swimmer’s itch, a harmless but annoying skin rash caused by microscopic parasites found in fresh and salt waters. Swimmer’s itch, also known as cercarial dermatitis, generally occurs in late July or August. It is a regular summertime nuisance throughout Connecticut and does not prompt beach closings.

The blame for the itchy skin condition lies with parasites that infect some birds and aquatic mammals. The parasite’s eggs are released into water by water fowl droppings. These eggs hatch into small larvae, which then infect the next host in the cycle, mud snails or other mollusks. After a short period of growth and under the right conditions, the parasite is released by the snail back into the water in a different type of larvae. The larvae, called cercariae, then seek to penetrate the skin of the water fowl and complete the cycle.

Unsuspecting humans can interrupt the cycle by swimming or wading in infected recreational waters. The cercariae mistake a bather’s skin as a host, instead of shorebirds, ducks, or geese. The parasite burrows into wet skin and dies. A cercariae cannot complete its life cycle in humans.

Bumps, resembling mosquito bites, develop on the skin as the body fights off the parasite.

According to the Connecticut State Department of Public Health, symptoms of swimmer’s itch include a tingling sensation that may be felt when the parasite enters the skin. A mild itching may occur within one to two hours after exposure and lasts for about an hour. A rash appears, 10 to 15 hours later, along with intense itching. The rash usually peaks in three to four days and disappears within a week.

Repeated exposure to the parasite may increase sensitivity and the chance of getting swimmer’s itch.

Most cases of swimmer’s itch do not require treatment. Try not to scratch, which can lead to secondary infection. Severe cases should be treated by a doctor.

Swimmer’s itch is not contagious; it cannot be spread from person to person.

In order to reduce the itching and inflammation you can:

  • Use corticosteroid cream
  • Apply cool compresses to the affected areas
  • Bathe in Epsom salts or baking soda
  • Soak in colloidal oatmeal baths
  • 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

Unfortunately, there are no sure fire ways to prevent this summertime ailment, but here are a few tips from the health district:

Do not swim or wade in areas where swimmer’s itch is a known problem. Ask the lifeguard on duty if there have been reported cases of swimmer’s itch recently before going into the water.

Do not swim near or wade in marshy areas where snails are commonly found.

Towel dry vigorously after swimming. This simple measure will destroy the parasite before it penetrates the skin.

Take a shower with warm water or rinse off, if possible. Dry off vigorously with a towel. A shower will rinse off the parasites, and get to any that may be inside a bathing suit.

Do not attract birds (e.g., by feeding them) to areas where people are swimming.

Do not walk barefoot through puddles on the beach, or in low tide or shallow water. Don’t let children sit or play on sand flats in low tide, particularly if there are mud spots.

Apply a waterproof sunscreen before swimming or walking in the water. The sunscreen helps form a “seal” so the parasite cannot burrow into the skin.

For more information visit:

  • cdc.gov/ncidod/dpd/parasites/cercarialdermatitis
  • ct.gov/dph/cwp