Swimmer's Itch

Swimmer's Itch aka "Duck Itch

What is swimmer's itch?

  • Swimmer's itch or schistosome cercarial dermatitis is a skin reaction that certain people have to the entry of a larval stage of certain flatworms into the epidermal layer of the skin. After the parasite enters, it dies and may cause dermatitis in individuals who have been previously sensitized. This sensitivity will rarely disappear; it usually get worse to subsequent exposures.

Will swimmer's itch spread?

  • No, a papule forms only where a cercaria has entered the skin of a person. If the person gets exposed to more cercariae, additional papules will form.

Why do children often develop the most severe cases of swimmer's itch?

  • They usually swim more regularly, their skin may be more sensitive, and young children have a tendency to stay near the water's edge. It appears that cercariae may concentrate near the shoreline.

What can be done to prevent or to reduce swimmer's itch?

  1. avoid swimming for long periods in shallow water
  2. avoid swimming in areas where swimmer's itch is a problem and where there is an onshore wind
  3. towel off immediately after leaving the water may help reducing swimmer's itch caused by cercariae of some species that enter only as the water dries on the skin
  4. post appropriate signs on beaches where swimmer's itch is an annual problem
  5. do not encourage birds to stay in your area by feeding them
  6. avoid placing rip-rap on your shore. This provides an excellent surface for certain species of snails to attach their eggs. The higher the number of snails, the greater the chance for swimmer's itch.

What can individuals do who have a bad case of swimmer's itch?

  • They should see a doctor and ask for a prescription to relieve the itching and for a topical cream that will reduce the swelling. Ken-tox is a nonprescription cream that gives relief.

-- Harvey B. Blankespoor & Ronald L. Reimink


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