A friend who knows I write health articles asked me about an awful red rash that had broken out all over the skin of one of his grandsons after swimming in the residential lake with his two brothers who were not affected. The quick-thinking adults gave the itchy kid an over-the-counter antihistamine which helped calm the angry, burning inflammation.
It didn’t take long to find out what was going on: swimmer’s itch (cercarial dermatitis). If you’ve never heard of it, you’re not alone. What I learned surprised me.
For one thing, people in New Jersey called the skin condition “Duckworms.” Ew.
The good news is that medical science knows all about swimmer’s itch: it is “a temporary, itchy rash caused by small worm-like parasites called schistosomes (shiss-toe-soams). Schistosomes spend their life cycle as parasites in the bodies of water snails and in the blood stream of aquatic mammals, ducks or other waterfowl. During their life cycle, schistosome larvae leave their snail host and swim near the surface of the water, looking for bird and mammal hosts.”
These sneaky little trematode parasites have suckers to attach themselves to new warm-blooded bodies. They flourish in warm, hot environments. Schistosomal infection is a known health risk for the 200 million people who live in the tropical belts around the Earth’s equator.
Wow. I, for one, did not see that coming. Little buggers (larvae, if you want to get technical) in the water lie in wait for unsuspecting swimmers to attack by burrowing under their skin, hoping to incubate in a new host animal. Ew! I may never wade into a lake again.
Granted, the larvae die in the process but leave behind the itchy skin rash. Scratching only makes it worse, possibly producing swelling, extreme pain, and skin infections.
During the warm months of summer, the parasitic larvae lurk near the surface and edges of lakes and other bodies of standing water.
Young kids with more sensitive skin are more likely to be afflicted with swimmer’s itch. They play by lake shores and stay wet without drying off for long periods of time, giving the larvae time to strike.
For most other people, the patchy red pinpoint skin rash lasts for a couple of days and goes away without any treatment.
A rash is a rash is a rash. Sometimes, telling the difference between swimmer’s itch and poison ivy itch is difficult. There is no specific test for swimmer’s itch. But recent swimming-in-a-lake-where-there-is-no-poison-ivy activity could help make a positive diagnosis.
Once a case of swimmer’s itch has been identified, there are some tried and true home remedies to try before calling 911 or seeking professional medical help:
- Apply plain calamine lotion
- Take antihistamines (may make young children sleepy; may stimulate the nervous system and cause hyperactivity)
- Apply a paste of baking soda and water to infected areas
- Apply an over-the-counter anti-itch cream
- Soak in shallow, lukewarm baths with 3 tablespoons of acid-neutralizing baking soda added to the water
- Take baths with a handful or two of Epsom salts or colloidal oatmeal
- Apply cool compresses (such as a wetted washcloth)
- Avoid scratching (the compress should stop you, junior)
Many lake properties post warning signs when it is known that the water has the schistosomes that cause swimmer’s itch. When in doubt, avoid areas overgrown with weeds because snails and larvae prefer those places.
Entering and exiting the water from a dock or pier also can help reduce the risk of exposure to the burrowing parasites.
After swimming in a lake, towel dry and shower off as soon as possible. This won’t stop any larvae which have already hitched a ride on your hide. They begin to burrow into the host’s skin, producing a tingling feeling. Tiny, pin-sized red spots appear and spread to become larger red rashes in the span of a few hours. The red spots grow as the tingling turns into a strong itch.
It may take 12 hours for the rash to show on someone infected with swimmer’s itch. The rash and other symptoms usually last two to five days but severe cases and those made worse by scratching can go on for up to two weeks.
The bad news is that subsequent infections are often worse since the host develops a sensitivity to the larvae and develops stronger physical reactions with each repeated exposure.
If the rash becomes too much to bear or if symptoms get worse, seek professional help. A prescription drug may resolve the unpleasant condition.