Swimmers’ itch is caused by a naturally occurring parasite that is carried from lake to lake by droppings from ducks, geese, or other waterfowl. The organisms then move into snails where they mature, eventually coming out to re-infect more waterfowl.
When human swimmers leave the water, any parasites on their skin may burrow into the skin in an effort to survive. The parasites die quickly, but they can trigger an irritating rash, said Joshua Meyerson, MD, Medical Director of the Northwest Michigan Community Health Agency, the health department that serves Antrim, Charlevoix, Emmet, and Otsego counties. "Your body reacts to the parasite by forming itchy, red bumps. Swimmers’ itch isn’t contagious, but it can be very uncomfortable."
Meyerson offers the following tips to reduce the chances of developing swimmers’ itch: briskly dry off with a towel as soon as you come out of the water, including the area under swimsuits, and shower immediately after swimming if facilities are available.
Not everyone who is exposed to the parasite will necessarily develop swimmers’ itch. “Repeated exposure increases sensitivity to the parasite and increases the likelihood of swimmers' itch,” Meyerson said. He said children are often infected with swimmers’ itch since they typically wade in and out of shallow water where the organism is predominately found and play on the beach as water evaporates on their skin.
Within minutes of swimming or wading in infested water, people may experience tingling, burning, or itchy skin. Or, symptoms may take up to a week to appear. A small, reddened bump will develop at the entrance site of each parasite, causing periods of itching that can last for several days.
Using calamine lotion, an antihistamine such as Benadryl or corticosteroid cream, cool compresses, baths with baking soda or colloidal oatmeal, such as Aveeno, may control itching. “The most important thing to do if you do contract swimmers’ itch is to try not to scratch. Scratching may cause the rash to become infected. If itching is severe, your health care provider may prescribe lotion or cream to lessen your symptoms,” Meyerson said.
Most cases of swimmers’ itch do not require medical attention. Contact your health care provider when the diagnosis is unclear, complications such as infection are present, or the reaction is intolerable.
Northwest Michigan Community Health Agency is mandated by the Michigan Public Health Code to promote wellness, prevent disease, provide quality healthcare, address health problems of vulnerable populations, and protect the environment for the residents and visitors of Antrim, Charlevoix, Emmet, and Otsego counties.