For many of us, swimming and playing in one of our many lakes or rivers is a favorite summer activity. But, your summer fun may turn into a summer bummer if you or your child gets swimmer’s itch. Just what is swimmer’s itch, how can you treat it, and most importantly, how can you prevent it?
What is swimmer’s itch?
Swimmer’s itch, or cercarial dermatitis, is an allergic reaction to parasitic larvae (cercariae) released by infected snails that live in shallow, marshy areas of lakes, ponds and rivers. This parasite lives in the blood of birds such as ducks and geese, and mammals such as muskrats and raccoons, and its eggs are released in feces. When the eggs hatch, in or near water, the larvae infect a certain species of snail, grow and develop, and complete the life cycle by searching for a host.
When you or your child play and swim in that same shallow water the newly hatched parasites may attach to you and burrow under your skin. Because humans are not good hosts, the parasites die under your skin causing an allergic reaction that shows up as red, itchy bumps or blisters.
Treatment for swimmer’s itch
The good news is that swimmer’s itch is not contagious. It is itchy and makes you very uncomfortable, but it usually clears up within a few days to a week. The old advice: try not to scratch. Scratching may lead to a bacterial infections.
Swimmer's itch most often does not require medical attention. To control the itch try these home remedies:
- Apply a paste made with baking soda and water to the rash.
- Apply cold packs or compresses to the affected areas.
- Bathe in cool water with Epsom salts or baking soda.
- Use over-the-counter anti-itch lotion or cortisone cream or ointment.
It’s hard to do, but try not to scratch. Scratching can cause the rash to become infected. If itching is severe or it looks like you’ve developed an infection, I may recommend a prescription lotion or cream. This can typically be done with an online visit, like Allina Health Virtual Care. This is especially convenient if symptoms start after clinic hours or over the weekend, since online visits are available 24/7.
How to prevent swimmer’s itch
The Minnesota Department of Health offers these tips to avoid swimmer’s itch:
- Do not swim in areas where swimmer's itch is a known problem or where signs have been posted warning of unsafe water.
- Do not swim near or wade in marshy areas where snails are commonly found.
- Towel dry or shower immediately after leaving the water.
- Do not attract birds (e.g., by feeding them) to areas where people are swimming.
- Be aware that winds blowing IN toward shore are more likely to bring in snails and cercariae that cause swimmer’s itch.