Swimmer’s itch: an unfortunate (but treatable) affliction during Alaska’s summertime

In the summertime, cercarial dermatitis – known to Alaskans by its colloquial name, “swimmer’s itch”— is a risk incurred at many of the major shore side recreation areas such as Tanana Lakes or Chena Lakes.

“Swimmer’s itch is caused by parasites that are present in water birds,” says Tanana Valley Clinic’s Dr. Richard Sheridan. “Typically you’ll pick it up at ponds and lakes that don’t have circulating water that have ducks or seagulls.”

There are many varieties of parasites which cause swimmer’s itch, but according to the CDC, it is a specific larval stage of these parasites, called “cercaria”, which burrow into human skin and cause an allergic reaction.

“It’ll typically manifest itself as little bumps underneath the skin about 12 hours after exposure to the contaminated water source,” Sheridan says. “On its own, it’ll typically last a few days.”

Sheridan says that the best way to avoid contracting swimmer’s itch is to avoid swimming in bodies of water with evidence of bird presence.

Barring this, there are several options for treating swimmer’s itch in the event it is contracted. “Some studies suggest that you can use waterproof sunscreen,” Sheridan says. “Apply that frequently.” He says that this may create an oil barrier between the parasites and the skin.

Another alternative is to immediately dry off after getting out of the water. “We tend to see swimmer’s itch more commonly in kids, cause kids don’t typically dry off when they get out of the water, then they want to run around and play,” Sheridan says. Residual moisture on bathing suits is also why swimmer’s itch is frequently found around those parts of the body.

“Should you get the swimmer’s itch, treatment is typically medicines to control the itching, which is basically the allergic reaction,” Sheridan advises. Over-the-counter hydrocortisone creams and antihistamines can help reduce the itching.

“The more you can resist [scratching], the better, because the more you [scratch] it the more it’s going to cause an inflammatory response, and it’s going to keep on going,” he says.

If over-the-counter medication does not work, or if signs of a secondary infection develop (such as firm redness or purulent drainage), “[that's] something you’d want to get checked out,” Sheridan says.

“Typically it’s a problem in the middle of the summer on the hot days when you’re most likely to go to Chena Lakes and go for a swim,” Sheridan says. Towards the end of summer, as the birds begin to migrate away from Alaska, cases begin to taper off.