Sea Lice Pose ‘Ocean Itch,’ Other Threats to Summertime Swimmers on the Gulf Coast

Published: June 15, 2016

Sea Lice Pose ‘Ocean Itch,’ Other Threats to Summertime Swimmers on the Gulf Coast

It’s a beautiful summer day along the sunny beaches of the Gulf Coast. You’re ready to enjoy the day, swim and relax. However, beneath the tepid water may lurk unwelcomed visitors. They’re neither sharks nor stingrays, but are part of the jellyfish family and not visible to the human eye.

Reports of the microscopic critters, known as sea lice, tend to invade summer waters in Florida and the Caribbean and have been known to inhabit Texas beaches. They have become a nuisance to swimmers. Sometimes referred to as the “ocean itch,” the most common reactions include itching and mild dermatitis, but more serious cases do occur and may require medical treatment for severe swelling, vomiting and extreme rash. Sea lice appear year round, but are most active between April and August.

For nearly a decade, Dr. Kim Withers, Assistant Professor of Biology at Texas A&M University-Corpus Christi, traveled each summer to Quintana Roo, Mexico, in the Mexican Caribbean, to teach Coral Reef Ecology. There, she has witnessed firsthand the displeasure that sea lice can have on unsuspecting swimmers.

“It was a significant problem during several of the trips,” she recalled. “Basically what happens is that the microscopic jellies get caught in bathing suits, usually wherever they are tight – under the arms, around the legs – and then when they get squished, they release nematocysts, known as stinging cells. Because of this, they are called “pica pica” in the Caribbean, which translates to ‘itchy, itchy’ in Spanish.”

Withers, who currently teaches classes on estuarine organisms, says stinging can also occur when you take a freshwater shower after getting out of the water – if you don’t remove the bathing suit first. 

“Loose clothing such as T-shirts can also be a problem because they trap the sea lice and you don’t know it until you get out of the water and the T-shirt sticks to you,” she added. 

Symptoms include an itchy, often raised, rash with red bumps or blisters, and you may not be aware that you have been stung usually until 24 hours later, when the rash appears. Sometimes the rash may be accompanied by fever, chills, headaches and nausea. Oftentimes, the rash is mild and clears up on its own, but in some cases, sea lice can produce flu-like symptoms that lasts for weeks. Children and individuals with compromised immune systems are most at risk for serious reactions.

“If you are in the water for just a little bit, it’s not a big deal,” Withers said. “It may be itchy and usually in the most uncomfortable places, like your crotch or under your breasts or arms. But if you are in the water multiple times a day, then it can actually be more serious. Some people are very sensitive to it, and also, sensitivity seems to increase over short time periods if you are consistently exposed.”