'Sea lice' are actually not-so-cute baby jellyfish

Story highlights

  • "Sea lice," a.k.a. ocean itch or seabather's eruption, are actually microscopic marine larvae
  • The larvae are as small as speck of pepper
  • Their stings can cause itchy red rash and flu-like symptoms

(CNN)Sea lice. Beach lice. Seabather's eruption. Pika-pika. Ocean itch. Those are just some of the names given to a rash caused by a minuscule creature that often invades summer waters in Florida and the Caribbean, pestering swimmers with nasty bumps and sometimes flu-like symptoms.

As tiny as a speck of pepper or the period at the end of this sentence, sea lice are not lice at all but the microscopic larvae of marine life such as jellyfish and sea anemones. (Sea lice is also the name of a fish parasite that does not affect humans.)
Sea lice are not lice at all by the microscopic larvae of marine life.
According to the Florida Department of Public Health, "sea lice" have been infesting coastal waters for more than a century, with most of the outbreaks traced to larvae of the thimble jellyfish, Linuche unguiculata.
    Though visible to the naked eye, these baby jellies disappear from sight in the water, making them impossible to avoid. They tend to migrate inside bathing suits, making their way through the mesh of the fabric, where they become trapped and begin to sting.
    Unlike with the adult's sting, it doesn't hurt. You won't know you've been stung until the rash appears, usually within 24 hours, sometimes along with fever, chills, headaches and nausea. The rash is often raised, with bumps or blisters that can be very red and extremely itchy.
    Sea lice, also known as seabather's eruption, can cause an itchy rash.