“Sea Lice” at the Beach is Not Really Lice

Sea Bather’s Eruption, commonly known as “sea lice,” is caused by a larval (microscopic) form of the thimble jellyfish and they have the same stinging cells as mommy and daddy.

These larvae are so small that they are barely visible, about the size of a speck of transparent salt.

When people swim in the affected ocean water, the larvae get caught in bathing suits, under arms, or any place where they become trapped.  Trapping them causes tiny stings. They especially get caught in bathing suit waistbands and straps or in wetsuits and fin straps on divers.  Sitting on a surfboard or laying on a boogie-board or float will cause the larvae to get trapped and fire wherever your skin contacts the flotation device.

You may or may not feel the stings right away.

The toxins that are released from these stings cause itching, irritation, and welts several hours later. The itching usually lasts 2-4 days, but can last as long as 2 weeks. Some people may have more severe reactions: headache, fever, nausea, and infected blisters. Children may develop high fever.

Prevention may be as simple as not swimming in the ocean when sea lice are present. There is no known topical lotion that has proven to work to stop the larvae from stinging.  If you do swim in the ocean, reduce the surface area of your swimwear; avoid wearing T-shirts or rash guards, and women might consider wearing a two piece suit to decrease skin exposure to trapped larvae.

Change out of your bathing suit as soon as possible after leaving the water. Fresh water causes the larvae stingers to fire so don’t shower with your suit on – where the larvae will get trapped.  Shower as soon as possible to rinse off loose larvae. If showers are in a public area, change into a second suit and then shower. Thoroughly wash the bathing suit with detergent in hot water and heat-dry after use.

If you do become affected by sea lice, an oral antihistamine, such as Benadryl, may help to relieve the itching. An over-the-counter topical 1% cortisone skin cream or sting aid may also be helpful. For severe reactions or complications, call your physician.

Episodes reported in Long Island waters are believed to be caused by the larval form of the sea anemone but have the same reaction and recommended treatment is the same.