What an itch! Swimmer’s edition

Close your eyes. You’re floating on your back (wearing a life preserver, most likely) at your favorite lake, with ducks and geese gently quacking as they feed nearby. Puffy clouds overhead, willows on the bank, and lily pads forming a soothing backdrop for your relaxing float.

And then a microscopic parasite burrows into your skin. You just got swimmer’s itch! 

swimmers itch image
Click to enlarge

What is swimmer’s itch?
Swimmer’s itch (cercarial dermatitis) is an itchy rash caused by a parasite in lake water. If you come into contact with water contaminated with parasites the microscopic parasites can burrow into the skin.

After burrowing into the skin, the parasite dies and the body reacts by forming red, itchy bumps. The itching and rash generally go away within about 5 – 6 days. Luckily, the parasites don’t spread from person to person.

Affected individuals should consult with their health care provider if the symptoms become severe or if the rash worsens or appears to become infected. Signs of infection are increased redness, pain, swelling, warmth, and possibly fever.

 

Tell me more about those parasites
The parasitic larvae that causes swimmer’s itch are deposited into lakes via goose and duck droppings. Then, they infect snails where they multiply and develop. The larvae then leave the snail looking for a bird or other suitable host. Humans are not suitable hosts, however the larvae can burrow into swimmer’s skin causing swimmers itch. Bottom line: duck poop is bad news.

via Mayo Foundation for Medical Education and Research
via Mayo Foundation for Medical Education and Research
Tips for reducing the risk of swimmer’s itch include:

  • Do not swim in areas where swimmer’s itch is a known problem.
  • Liberally apply a waterproof sunscreen prior to swimming. There is evidence that this may provide some protection.
  • Briskly dry off with a towel as soon as you come out of the water, including the skin under the swimsuit.
  • Shower immediately if these facilities are available.
  • Do not feed ducks and geese. This may attract more of these birds to the area and increase contamination of the water and shoreline.
  • Avoid swimming in marshy areas where snails are commonly found, particularly places with lily pads.

Most cases of swimmer’s itch do not require medical attention. If you have a rash, you may try the following for relief:

  • 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.

Editorial note: This is post is part of the “What an itch!” series, where we tell you all about stuff that makes you scratch.