Swimmer's itch, also called schistosome dermatitis, appears as a skin rash caused by an allergic reaction to certain microscopic parasites that infect some birds and mammals. These parasites are released from infected snails into fresh and salt water (such as lakes, ponds, and oceans). While the parasite's preferred host is the specific bird or mammal, if the parasite comes into contact with a swimmer, it burrows into the skin causing an allergic reaction and rash. Swimmer's itch is found throughout the world and is more frequent during summer months.
Symptoms of swimmer's itch may include:
Within minutes to days after swimming in contaminated water, you may experience tingling, burning, or itching of the skin. Scratching the areas may result in secondary bacterial infections. Itching may last up to a week or more, but will gradually go away. If itching is severe, your health care provider may prescribe lotion or creams to lessen your symptoms. If your symptoms persist, see your doctor.
Because swimmer's itch is caused by an allergic reaction to infection, the more often you swim or wade in contaminated water, the more likely you are to develop more serious symptoms. The greater the number of exposures to contaminated water, the more intense and immediate symptoms of swimmer's itch will be.
Be aware that swimmer's itch is not the only rash that may occur after swimming in fresh or salt water.
Anyone who swims or wades in infested water may be at risk. Larvae 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.
To reduce the likelihood of developing swimmer's itch:
Adapted from the Centres for Disease Control and Prevention.