Taking a cool dip in one of Whistler's lakes is one of the best ways to beat the heat on a hot, sunny summer weekend.
The potential downside? A rash of red, itchy bumps that may or may not pop up a few hours after your swim.
The Resort Municipality of Whistler (RMOW) said it's received numerous reports of swimmer's itch caught in Whistler lakes throughout the month of July, especially within the last week or so and particularly from visitors of Alta Lake's Wayside and Lakeside Parks. Locals have also taken to social media in recent days to warn neighbours about swimmer's itch in Alpha and Green Lakes.
Visitors to those lakes could notice signs posted in the local lake-shore parks warning that swimmer’s itch may be present.
What is swimmer's itch?
Swimmer's itch, sometimes referred to as "duck itch" or "lake itch," is a temporary but irritating skin rash caused by an allergic reaction to small, worm-like parasites called schistosomes. Those microscopic parasites are most often found in freshwater like lakes or ponds, but sometimes occur in salt water, and have been reported in bodies of water throughout B.C. and the rest of North America.
Swimmer's itch poses no serious risk to health.
As HealthLink BC explains on its website, schistosomes are typically found in water snails and in the blood stream of aquatic mammals, like ducks. However, schistosome larvae will eventually leave those hosts and swim near the water's surface in search of bird and mammal hosts. They're more typically found in shallower waters near the shore.
If a person is wading or swimming in a spot with those larvae around, there's a chance the parasites could burrow into the swimmer's skin. The good news? Humans aren't suitable hosts for the larvae, so they'll die almost immediately. The not-so-great news is the allergic reaction could stick around.
The itchy rashes typically last around two to five days, though symptoms can linger for as long as two weeks, according to HeathLink BC.
A swimmer could start to feel a tingling sensation and notice small, pin-sized red spots appear as soon as they begin drying off. Those spots may grow into larger, redder rashes within a matter of hours, while the tingling could morph into a strong itch.
Symptoms can reportedly range from a mild irritation to a severe, itchy red rash. Scratching can worsen the rash or even cause a skin infection. The severity of the allergic reaction depends on how many larvae burrow into the skin, and how sensitive an individual is to the tiny intruders.
Those symptoms tend to intensify with repeat infections, as "People become more sensitive to the larvae and develop stronger responses each time," explains HealthLink BC.
Swimmer's itch cannot be spread from person to person.
How to prevent swimmer's itch
The only foolproof way to avoid swimmer's itch completely is to stay out of the water, but if you can't say no to an inviting lake on a hot summer day, there are a few strategies to lessen the risk.
According to public health officials, swimmer's itch can be avoided by entering the water from a dock rather than wading in from shore and by staying out of shallow water. Lake-goers can also prevent the itch by rinsing off or showering (public outdoor showers are available at some Whistler parks, like Lakeside) and towelling off immediately after swimming.
Those who do develop an itchy reaction can use calamine lotion and cool compresses or take antihistamines or shallow, lukewarm baths with baking soda to ease the discomfort.
