Stinging sea lice are out in SC oceans this summer. Here’s how to deal with them

As millions of people journey to South Carolina beaches this summer, some will share the water with unwelcome companions. Dubbed sea poisoning, ocean itch and even seabather’s eruption, sea lice can sully a beach day with itchy, stinging rashes.

Despite their parasitic moniker, sea lice aren’t actually lice. They don’t suck blood or have much in common with head lice.

“’Sea lice’ is an umbrella term that many people use to describe a wide variety of tiny, stinging plankton or nekton,” said South Carolina Department of Natural Resources spokesperson Erin Weeks in an email. “These can include sea butterflies (pteropods, a type of sea snails), jellyfish larvae, blue crab larvae, and other unidentified crustacean larvae.”

Here’s what beachgoers should know about these tiny, sometimes painful, sea creatures before hitting the coast this summer.

Why sea lice irritate swimmers

While they don’t bite, sea lice irritate skin, especially around hair and apparel. The tiny creatures are too small to be identified by the human eye, but leave behind irritating rashes, which Tidelands Health Family Medicine physician Dr. Sean Nguyen describes as similar to poison ivy and other contact rashes.

“It’s really not the direct contact with your skin,” Nguyen said. “When you go in the water, it’s areas where the ‘lice’ or larvae are getting between your hair that’s wet, or your bathing suit, or anywhere if you’re wearing a rash guard or any type of shirt, it just gets in between that space and kind of irritates.”

The severity and scale of a rash depends on the sea lice encountered and how a person’s skin reacts.

Where are sea lice found?

Sea lice are found in salt water across South Carolina’s coast. The speck-sized creatures get carried by the tides, so if you or someone else on the beach encounters them, it’s probably best to steer clear for a while.

“Because they are often plankton, which drift with the currents, ‘sea lice’ tend to be quite localized,” Weeks said. “If they’ve been reported in the area, you can often wait or try another stretch of beach to avoid them.”

When are sea lice most common?

People tend to encounter sea lice most often in the summer.

“These aren’t well studied and it’s difficult to speak in general terms about a number of different organisms, but, naturally, reports are highest in the hot summer months when the largest number of beachgoers are in the ocean,” Weeks said.

While it’s unclear if certain species are more populous along South Carolina’s coast in the summer, Nguyen agrees human contact is most frequent during the vacation season.

“We say about April to August, that’s when the waters usually have the highest possibility of having these ‘lice’ in the water,” said Nguyen. “That’s when you’re going to come into contact with them.”

Removing sea lice from clothes

Nguyen says swimmers affected by sea lice should exit the water as soon as they notice irritation and remove swimwear and clothes as quickly as possible. Because sea lice can get trapped in apparel, it’s better to thoroughly rinse the body and hair off in the nude.

After swimwear and clothing have trapped sea lice, it’s a good idea to thoroughly wash them. Exposure to heat can also help kill any remaining sea lice left over. But ultimately, if apparel continues to cause issues, it may be time to part ways.

“If it’s just severely irritating, your skin is breaking out, sometimes we recommend just getting rid of the bathing suit, if you feel like it’s still irritating you even after you’ve cleaned it,” Nguyen said.

How to treat sea lice

Once people stung are rid of their apparel, it’s best to rinse off as soon as possible. Although Nguyen generally recommends using lukewarm water, temperature can be adjusted hot or cold, depending on what’s comfortable and provides relief from itching and stinging.

Rinsing with saltwater and acidic solutions like vinegar can also help dislodge or neutralize stinging cells from the sea lice, according to Weeks.

After the area is clean, topical treatments like ice or aloe can help manage discomfort or pain. Similar to insect bite treatments, topical creams can also help ease irritation and slow a rash after skin is exposed to a toxin.

“What you’re trying to do is kind of prevent the spread of the rash,” said Nguyen. “Once your body kind of recognizes that it’s been foreign body or foreign irritation is there, it tries to create a chain reaction to create a larger rash.”

For milder rashes, antihistamine cream and calamine lotion may help, while more severe irritation may benefit from steroid creams. No matter how badly a rash itches, it’s important to resist the urge to scratch, which will irritate the skin further.

“Most of these rashes will go away on its own once you get away from the exposure,” Nguyen said. “Some people will have to take an antihistamine, an allergy pill, a Zyrtec, a Benadryl to calm the rash down.”

When to seek medical help

While most sea lice rashes heal with little issue, some people may experience complications. Nguyen recommends reaching out to a doctor or medical provider if exposure produces more severe reactions, like fever, headache or nausea.

“I tell all my patients, if it’s something you just want any provider to look at, contact your doctor,” Nguyen said.

This story was originally published July 5, 2025 at 6:00 AM with the headline "Stinging sea lice are out in SC oceans this summer. Here’s how to deal with them."