What Are Sea Lice?

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First thing's first. Sea lice aren't lice at all. They're tiny baby jellyfish, so small you can't even see them -- about the size of a grain of pepper. And just like their grownup counterparts, they sting.

The trouble comes when these babies get caught between your skin and your bathing suit, or even in your hair. About 4-24 hours later, you start to itch and sting. And you get a red rash that looks like acne and lasts about a week.

Here's how to avoid sea lice:

Wear just your bathing suit. Fewer clothes means fewer places for them to get trapped. Actually skinny dipping is best, but would cause other problems at the beach!

Change out of your suit as soon as you can, and take a shower with no clothes on. Don't shower in your suit, because freshwater actually causes the stinging cells to release more venom.

Wash your bathing suit with laundry detergent and put it in the dryer. Heat will kill any of the remaining stingers.

If you do get a rash, you can take an antihistamine or use a cream to relieve the itch. If you feel nauseous, have diarrhea, headaches, muscle spasms or trouble sleeping, go see a doctor. For WebMD, I'm Dr. Michael Smith.