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Communicable Disease Control

Epidemiology

Utah Public Health Lab

 


Swimmer's Itch
(Cercarial Dermatitis)

 

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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 some birds and mammals. These microscopic parasites are released from infected snails into fresh and salt water (such as lakes, ponds, and oceans). The parasite then burrows into the nearby swimmer's skin, causing an allergic reaction and rash. Swimmer's itch generally occurs during the summer months.

What are the sign and symptoms of swimmer’s itch?
Symptoms of swimmer's itch may include

  • tingling, burning, or itching of the skin (may occur within minutes to days)
  • small reddish pimples (occurs within 12 hours)
  • small blisters (may occur after the pimples appear)

Because swimmer's itch is caused by an allergic reaction to infection, continual exposure to contaminated water increases the likelihood of developing serious symptoms. Since swimmer’s itch is an allergic reaction, only about 30-40% of people will be affected.

Be aware that swimmer's itch is not the only rash that may occur after swimming in fresh and salt water.

Do I need to see my health care provider for treatment?
Most cases of swimmer's itch do not require medical attention; however, if you experience a fever or other severe symptoms you may want to see a doctor. If you have a rash, you may try the following for relief:

  • Use over-the-counter oral antihistamine
  • Use topical anti-itch creams and ointments that relieve itching
  • Apply coll compresses to the affected areas
  • Bathe in Epson salts or baking soda

Though difficult, try not to scratch. Scratching may cause the rash to become infected. If itching is severe, your health care provider may suggest prescription-strength lotions or creams to lessen your symptoms.

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.

Who is at risk for swimmer’s itch?
Anyone who swims or wades in infested water may be at risk. The parasites 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.

Once an outbreak of swimmer’s itch has occurred in water, will the water always be unsafe?
No. Many factors must be present for swimmer's itch to become a problem in water. Since these factors change (sometimes within a swim season) swimmer's itch will not always be a problem. However, there is no way to know how long water may be unsafe.

Is it safe to swim in my swimming pool?
Yes, as long as your swimming pool is well maintained and chlorinated, there is no risk of swimmer’s itch.

What can be done to reduce the risk of swimmer’s itch?
To reduce the likelihood of developing swimmer's itch

  1. Do not swim in areas where swimmer's itch is a known problem or where signs have been posted warning of unsafe water
  2. Do not swim or wade in marshy areas where snails are commonly found.
  3. Towel dry or shower immediately after leaving the water.
  4. Do not attract birds (e.g., feeding them) to areas where people are swimming.
  5. Encourage health officials to post signs on shorelines where swimmer's itch is a current problem.
  6. Wear sun-block or petroleum jelly when swimming in areas prone to swimmer's itch.

Where can I get more information?

  1. Your personal doctor.
  2. Your local health department listed in your telephone directory.
  3. The Utah Department of Health, Bureau of Epidemiology (801)536-6191.
  4. Or visit this link:

 

Utah Department of Health
Bureau of Epidemiology
11/28/2006